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Neuenschwander FR, Groß B, Schubert S. Rapid Antibiotic Susceptibility Testing of Gram-Negative Bacteria Directly from Urine Samples of UTI Patients Using MALDI-TOF MS. Antibiotics (Basel) 2023; 12:1042. [PMID: 37370361 DOI: 10.3390/antibiotics12061042] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
Urinary tract infections (UTIs) are one of the most common human infections and are most often caused by Gram-negative bacteria such as Escherichia coli. In view of the increasing number of antibiotic-resistant isolates, rapidly initiating effective antibiotic therapy is essential. Therefore, a faster antibiotic susceptibility test (AST) is desirable. The MALDI-TOF MS-based phenotypic antibiotic susceptibility test (MALDI AST) has been used in blood culture diagnostics to rapidly detect antibiotic susceptibility. This study demonstrates for the first time that MALDI AST can be used to rapidly determine antibiotic susceptibility in UTIs directly from patients' urine samples. MALDI-TOF MS enables the rapid identification and AST of Gram-negative UTIs within 4.5 h of receiving urine samples. Six urinary tract infection antibiotics, including ciprofloxacin, cotrimoxazole, fosfomycin, meropenem, cefuroxime, and nitrofurantoin, were analyzed and compared with conventional culture-based AST methods. A total of 105 urine samples from UTI patients contained bacterial isolates for MALDI AST. The combination of ID and AST by MALDI-TOF allowed us to interpret the result according to EUCAST guidelines. An overall agreement of 94.7% was found between MALDI AST and conventional AST for the urinary tract pathogens tested.
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Affiliation(s)
- Felix R Neuenschwander
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Elisabeth-Winterhalter-Weg 6, 81377 Munich, Germany
| | - Birgit Groß
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Elisabeth-Winterhalter-Weg 6, 81377 Munich, Germany
| | - Sören Schubert
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Elisabeth-Winterhalter-Weg 6, 81377 Munich, Germany
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2
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Marutescu LG. Current and Future Flow Cytometry Applications Contributing to Antimicrobial Resistance Control. Microorganisms 2023; 11:1300. [PMID: 37317273 DOI: 10.3390/microorganisms11051300] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 06/16/2023] Open
Abstract
Antimicrobial resistance is a global threat to human health and welfare, food safety, and environmental health. The rapid detection and quantification of antimicrobial resistance are important for both infectious disease control and public health threat assessment. Technologies such as flow cytometry can provide clinicians with the early information, they need for appropriate antibiotic treatment. At the same time, cytometry platforms facilitate the measurement of antibiotic-resistant bacteria in environments impacted by human activities, enabling assessment of their impact on watersheds and soils. This review focuses on the latest applications of flow cytometry for the detection of pathogens and antibiotic-resistant bacteria in both clinical and environmental samples. Novel antimicrobial susceptibility testing frameworks embedding flow cytometry assays can contribute to the implementation of global antimicrobial resistance surveillance systems that are needed for science-based decisions and actions.
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Affiliation(s)
- Luminita Gabriela Marutescu
- Department of Botany and Microbiology, Faculty of Biology, University of Bucharest, 91-95 Spl. Independentei, 050095 Bucharest, Romania
- Research Institute of the University of Bucharest, 050095 Bucharest, Romania
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3
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Hatipoglu H, Erman G, Toptan H, Koroglu M, Altindis M. Determination of antibiotic susceptibility of bacteria by flow cytometric method. World J Microbiol Biotechnol 2022; 38:151. [PMID: 35781757 DOI: 10.1007/s11274-022-03332-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/10/2022] [Indexed: 11/24/2022]
Abstract
In this study, it was aimed to determine the antibiotic susceptibility of bacterial strains by using flow cytometry method by comparing them with current standardized methods. Eleven clinical isolates and 6 standard bacterial strains were included in the study. MIC values were determined by broth microdilution method (BMD), VITEK 2® automated system and flow cytometric method (FCM). FCM was performed with the Accuri C6 flow cytometer. For all strains except P. aeuruginosa ATCC 27853 [BMD-FCM:r = 0.557(p = 0.048); VITEK 2-FCM:r = 0.529(p = 0.063)], E. faecalis ATCC 29212 [BMD-FCM:r = 0.393(p = 0.295); BMD-VITEK 2:r = 0.393(p = 0.295)], and vancomycin-resistant E. faecium clinical isolate [BMD-FCM:r = 0.452(p = 0.063)] r values were in the range of 0.802-0.969 for BMD-FCM (p < 0.001), 0.655-0.941 for BMD-VITEK 2 (p < 0.005) and 0.667-0.953 for FCM-VITEK 2 (p < 0.005). Correlation values of antibiotic susceptibility test results between three methods for Gram-negative bacteria were found as follows; r = 0.927(p < 0.001) for BMD-FCM, r = 0.851(p < 0.001) for BMD-VITEK 2, r = 0.807(p < 0.001) for VITEK 2-FCM. Correlation values were found as follows for Gram positive bacteria; r = 0.848(p < 0.001) for BMD-FCM, r = 0.877(p < 0.001) for BMD-VITEK 2, r = 0.800(p < 0.001) for VITEK 2-FCM. When all bacteria included in the study were evaluated as a total; it was r = 0.911(p < 0.001) for BMD-FCM, r = 0.888(p < 0.001) for BMD-VITEK 2, r = 0.835(p < 0.001) for VITEK 2-FCM. The methicillin resistance of the clinical methicillin resistant S. aureus isolate could not be detected by FCM. It was determined that there was a high level of correlation between methods. FCM shortens the duration of antibiotic susceptibility tests by 12-14 h and gives results within the same day. However, it has not been standardized to be widely used in microbiology laboratories and experienced personnel are needed for its implementation.
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Affiliation(s)
- Huseyin Hatipoglu
- Department of Medical Microbiology, Faculty of Medicine, Sakarya University, Sakarya, Turkey
| | - Gulay Erman
- Health Services Education Research and Application Centre, Sakarya University, Sakarya, Turkey
| | - Hande Toptan
- Medical Microbiology Laboratory, Sakarya Training and Research Hospital, Sakarya, Turkey.
| | - Mehmet Koroglu
- Department of Medical Microbiology, Faculty of Medicine, Sakarya University, Sakarya, Turkey
| | - Mustafa Altindis
- Department of Medical Microbiology, Faculty of Medicine, Sakarya University, Sakarya, Turkey
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Filbrun AB, Richardson JC, Khanal PC, Tzeng Y, Dickson RM. Rapid, label‐free antibiotic susceptibility determined directly from positive blood culture. Cytometry A 2022; 101:564-576. [DOI: 10.1002/cyto.a.24560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 03/19/2022] [Accepted: 04/06/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Alexandra B. Filbrun
- School of Chemistry and Biochemistry and Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA
| | - Joseph C. Richardson
- School of Chemistry and Biochemistry and Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA
| | - Prakash C. Khanal
- School of Chemistry and Biochemistry and Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA
| | - Yih‐Ling Tzeng
- Division of Infectious Disease, Department of Medicine Emory University School of Medicine Atlanta GA
| | - Robert M. Dickson
- School of Chemistry and Biochemistry and Petit Institute of Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA
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5
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Salcedo-Sora JE, Robison ATR, Zaengle-Barone J, Franz KJ, Kell DB. Membrane Transporters Involved in the Antimicrobial Activities of Pyrithione in Escherichia coli. Molecules 2021; 26:molecules26195826. [PMID: 34641370 PMCID: PMC8510280 DOI: 10.3390/molecules26195826] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 02/06/2023] Open
Abstract
Pyrithione (2-mercaptopyridine-N-oxide) is a metal binding modified pyridine, the antibacterial activity of which was described over 60 years ago. The formulation of zinc-pyrithione is commonly used in the topical treatment of certain dermatological conditions. However, the characterisation of the cellular uptake of pyrithione has not been elucidated, although an unsubstantiated assumption has persisted that pyrithione and/or its metal complexes undergo a passive diffusion through cell membranes. Here, we have profiled specific membrane transporters from an unbiased interrogation of 532 E. coli strains of knockouts of genes encoding membrane proteins from the Keio collection. Two membrane transporters, FepC and MetQ, seemed involved in the uptake of pyrithione and its cognate metal complexes with copper, iron, and zinc. Additionally, the phenotypes displayed by CopA and ZntA knockouts suggested that these two metal effluxers drive the extrusion from the bacterial cell of potentially toxic levels of copper, and perhaps zinc, which hyperaccumulate as a function of pyrithione. The involvement of these distinct membrane transporters contributes to the understanding of the mechanisms of action of pyrithione specifically and highlights, more generally, the important role that membrane transporters play in facilitating the uptake of drugs, including metal-drug compounds.
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Affiliation(s)
- Jesus Enrique Salcedo-Sora
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown St., Liverpool L69 7ZB, UK
- Correspondence: (J.E.S.-S.); (K.J.F.); (D.B.K.)
| | - Amy T. R. Robison
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA; (A.T.R.R.); (J.Z.-B.)
| | - Jacqueline Zaengle-Barone
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA; (A.T.R.R.); (J.Z.-B.)
| | - Katherine J. Franz
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA; (A.T.R.R.); (J.Z.-B.)
- Correspondence: (J.E.S.-S.); (K.J.F.); (D.B.K.)
| | - Douglas B. Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown St., Liverpool L69 7ZB, UK
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kgs Lyngby, Denmark
- Correspondence: (J.E.S.-S.); (K.J.F.); (D.B.K.)
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6
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Son B, Patterson-West J, Arroyo-Mendoza M, Ramachandran R, Iben J, Zhu J, Rao V, Dimitriadis E, Hinton D. A phage-encoded nucleoid associated protein compacts both host and phage DNA and derepresses H-NS silencing. Nucleic Acids Res 2021; 49:9229-9245. [PMID: 34365505 PMCID: PMC8450097 DOI: 10.1093/nar/gkab678] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 07/20/2021] [Accepted: 08/06/2021] [Indexed: 12/23/2022] Open
Abstract
Nucleoid Associated Proteins (NAPs) organize the bacterial chromosome within the nucleoid. The interaction of the NAP H-NS with DNA also represses specific host and xenogeneic genes. Previously, we showed that the bacteriophage T4 early protein MotB binds to DNA, co-purifies with H-NS/DNA, and improves phage fitness. Here we demonstrate using atomic force microscopy that MotB compacts the DNA with multiple MotB proteins at the center of the complex. These complexes differ from those observed with H-NS and other NAPs, but resemble those formed by the NAP-like proteins CbpA/Dps and yeast condensin. Fluorescent microscopy indicates that expression of motB in vivo, at levels like that during T4 infection, yields a significantly compacted nucleoid containing MotB and H-NS. motB overexpression dysregulates hundreds of host genes; ∼70% are within the hns regulon. In infected cells overexpressing motB, 33 T4 late genes are expressed early, and the T4 early gene repEB, involved in replication initiation, is up ∼5-fold. We postulate that MotB represents a phage-encoded NAP that aids infection in a previously unrecognized way. We speculate that MotB-induced compaction may generate more room for T4 replication/assembly and/or leads to beneficial global changes in host gene expression, including derepression of much of the hns regulon.
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Affiliation(s)
- Bokyung Son
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jennifer Patterson-West
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Melissa Arroyo-Mendoza
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Revathy Ramachandran
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - James R Iben
- Molecular Genomics Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Jingen Zhu
- Department of Biology, The Catholic University of America, Washington, DC, USA
| | - Venigalla Rao
- Department of Biology, The Catholic University of America, Washington, DC, USA
| | - Emilios K Dimitriadis
- Trans-NIH Shared Resource on Biomedical Engineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Deborah M Hinton
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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Kell DB. The Transporter-Mediated Cellular Uptake and Efflux of Pharmaceutical Drugs and Biotechnology Products: How and Why Phospholipid Bilayer Transport Is Negligible in Real Biomembranes. Molecules 2021; 26:5629. [PMID: 34577099 PMCID: PMC8470029 DOI: 10.3390/molecules26185629] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/03/2021] [Accepted: 09/14/2021] [Indexed: 12/12/2022] Open
Abstract
Over the years, my colleagues and I have come to realise that the likelihood of pharmaceutical drugs being able to diffuse through whatever unhindered phospholipid bilayer may exist in intact biological membranes in vivo is vanishingly low. This is because (i) most real biomembranes are mostly protein, not lipid, (ii) unlike purely lipid bilayers that can form transient aqueous channels, the high concentrations of proteins serve to stop such activity, (iii) natural evolution long ago selected against transport methods that just let any undesirable products enter a cell, (iv) transporters have now been identified for all kinds of molecules (even water) that were once thought not to require them, (v) many experiments show a massive variation in the uptake of drugs between different cells, tissues, and organisms, that cannot be explained if lipid bilayer transport is significant or if efflux were the only differentiator, and (vi) many experiments that manipulate the expression level of individual transporters as an independent variable demonstrate their role in drug and nutrient uptake (including in cytotoxicity or adverse drug reactions). This makes such transporters valuable both as a means of targeting drugs (not least anti-infectives) to selected cells or tissues and also as drug targets. The same considerations apply to the exploitation of substrate uptake and product efflux transporters in biotechnology. We are also beginning to recognise that transporters are more promiscuous, and antiporter activity is much more widespread, than had been realised, and that such processes are adaptive (i.e., were selected by natural evolution). The purpose of the present review is to summarise the above, and to rehearse and update readers on recent developments. These developments lead us to retain and indeed to strengthen our contention that for transmembrane pharmaceutical drug transport "phospholipid bilayer transport is negligible".
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Affiliation(s)
- Douglas B. Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown St, Liverpool L69 7ZB, UK;
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kgs Lyngby, Denmark
- Mellizyme Biotechnology Ltd., IC1, Liverpool Science Park, Mount Pleasant, Liverpool L3 5TF, UK
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8
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Salcedo-Sora JE, Jindal S, O'Hagan S, Kell DB. A palette of fluorophores that are differentially accumulated by wild-type and mutant strains of Escherichia coli: surrogate ligands for profiling bacterial membrane transporters. MICROBIOLOGY (READING, ENGLAND) 2021; 167:001016. [PMID: 33406033 PMCID: PMC8131027 DOI: 10.1099/mic.0.001016] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022]
Abstract
Our previous work demonstrated that two commonly used fluorescent dyes that were accumulated by wild-type Escherichia coli MG1655 were differentially transported in single-gene knockout strains, and also that they might be used as surrogates in flow cytometric transporter assays. We summarize the desirable properties of such stains, and here survey 143 candidate dyes. We eventually triage them (on the basis of signal, accumulation levels and cost) to a palette of 39 commercially available and affordable fluorophores that are accumulated significantly by wild-type cells of the 'Keio' strain BW25113, as measured flow cytometrically. Cheminformatic analyses indicate both their similarities and their (much more considerable) structural differences. We describe the effects of pH and of the efflux pump inhibitor chlorpromazine on the accumulation of the dyes. Even the 'wild-type' MG1655 and BW25113 strains can differ significantly in their ability to take up such dyes. We illustrate the highly differential uptake of our dyes into strains with particular lesions in, or overexpressed levels of, three particular transporters or transporter components (yhjV, yihN and tolC). The relatively small collection of dyes described offers a rapid, inexpensive, convenient and informative approach to the assessment of microbial physiology and phenotyping of membrane transporter function.
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Affiliation(s)
- Jesus Enrique Salcedo-Sora
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown St, Liverpool L69 7ZB, UK
| | - Srijan Jindal
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown St, Liverpool L69 7ZB, UK
| | - Steve O'Hagan
- Department of Chemistry and Manchester Institute of Biotechnology, The University of Manchester, 131 Princess St, Manchester M1 7DN, UK
| | - Douglas B. Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown St, Liverpool L69 7ZB, UK
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kgs Lyngby, Denmark
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9
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Zhou K, Zhou C, Sapre A, Pavlock JH, Weaver A, Muralidharan R, Noble J, Chung T, Kovac J, Liu Z, Ebrahimi A. Dynamic Laser Speckle Imaging Meets Machine Learning to Enable Rapid Antibacterial Susceptibility Testing (DyRAST). ACS Sens 2020; 5:3140-3149. [PMID: 32942846 DOI: 10.1021/acssensors.0c01238] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Rapid antibacterial susceptibility testing (RAST) methods are of significant importance in healthcare, as they can assist caregivers in timely administration of the correct treatments. Various RAST techniques have been reported for tracking bacterial phenotypes, including size, shape, motion, and redox state. However, they still require bulky and expensive instruments-which hinder their application in resource-limited environments-and/or utilize labeling reagents which can interfere with antibiotics and add to the total cost. Furthermore, the existing RAST methods do not address the potential gradual adaptation of bacteria to antibiotics, which can lead to a false diagnosis. In this work, we present a RAST approach by leveraging machine learning to analyze time-resolved dynamic laser speckle imaging (DLSI) results. DLSI captures the change in bacterial motion in response to antibiotic treatments. Our method accurately predicts the minimum inhibitory concentration (MIC) of ampicillin and gentamicin for a model strain of Escherichia coli (E. coli K-12) in 60 min, compared to 6 h using the currently FDA-approved phenotype-based RAST technique. In addition to ampicillin (a β-lactam) and gentamicin (an aminoglycoside), we studied the effect of ceftriaxone (a third-generation cephalosporin) on E. coli K-12. The machine learning algorithm was trained and validated using the overnight results of a gold standard antibacterial susceptibility testing method enabling prediction of MIC with a similarly high accuracy yet substantially faster.
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Affiliation(s)
- Keren Zhou
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Chen Zhou
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Anjali Sapre
- Department of Food Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jared Henry Pavlock
- Department of Food Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ashley Weaver
- Department of Food Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ritvik Muralidharan
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Josh Noble
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Taejung Chung
- Department of Food Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jasna Kovac
- Department of Food Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Zhiwen Liu
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Aida Ebrahimi
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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10
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Jindal S, Yang L, Day PJ, Kell DB. Involvement of multiple influx and efflux transporters in the accumulation of cationic fluorescent dyes by Escherichia coli. BMC Microbiol 2019; 19:195. [PMID: 31438868 PMCID: PMC6704527 DOI: 10.1186/s12866-019-1561-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/31/2019] [Indexed: 12/11/2022] Open
Abstract
Background It is widely believed that most xenobiotics cross biomembranes by diffusing through the phospholipid bilayer, and that the use of protein transporters is an occasional adjunct. According to an alternative view, phospholipid bilayer transport is negligible, and several different transporters may be involved in the uptake of an individual molecular type. We recognise here that the availability of gene knockout collections allows one to assess the contributions of all potential transporters, and flow cytometry based on fluorescence provides a convenient high-throughput assay for xenobiotic uptake in individual cells. Results We used high-throughput flow cytometry to assess the ability of individual gene knockout strains of E coli to take up two membrane-permeable, cationic fluorescent dyes, namely the carbocyanine diS-C3(5) and the DNA dye SYBR Green. Individual strains showed a large range of distributions of uptake. The range of modal steady-state uptakes for the carbocyanine between the different strains was 36-fold. Knockouts of the ATP synthase α- and β-subunits greatly inhibited uptake, implying that most uptake was ATP-driven rather than being driven by a membrane potential. Dozens of transporters changed the steady-state uptake of the dye by more than 50% with respect to that of the wild type, in either direction (increased or decreased); knockouts of known influx and efflux transporters behaved as expected, giving credence to the general strategy. Many of the knockouts with the most reduced uptake were transporter genes of unknown function (‘y-genes’). Similarly, several overexpression variants in the ‘ASKA’ collection had the anticipated, opposite effects. Similar results were obtained with SYBR Green (the range being approximately 69-fold). Although it too contains a benzothiazole motif there was negligible correlation between its uptake and that of the carbocyanine when compared across the various strains (although the membrane potential is presumably the same in each case). Conclusions Overall, we conclude that the uptake of these dyes may be catalysed by a great many transporters of putatively broad and presently unknown specificity, and that the very large range between the ‘lowest’ and the ‘highest’ levels of uptake, even in knockouts of just single genes, implies strongly that phospholipid bilayer transport is indeed negligible. This work also casts serious doubt upon the use of such dyes as quantitative stains for representing either bioenergetic parameters or the amount of cellular DNA in unfixed cells (in vivo). By contrast, it opens up their potential use as transporter assay substrates in high-throughput screening. Electronic supplementary material The online version of this article (10.1186/s12866-019-1561-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Srijan Jindal
- Department of Chemistry, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.,Manchester Institute of Biotechnology, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.,Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Lei Yang
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kgs, Lyngby, Denmark
| | - Philip J Day
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.,Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Douglas B Kell
- Department of Chemistry, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK. .,Manchester Institute of Biotechnology, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK. .,Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kgs, Lyngby, Denmark. .,Department of Biochemistry, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown St, Liverpool, L69 7ZB, UK.
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