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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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Cai J, Nichols RG, Koo I, Kalikow ZA, Zhang L, Tian Y, Zhang J, Smith PB, Patterson AD. Multiplatform Physiologic and Metabolic Phenotyping Reveals Microbial Toxicity. mSystems 2018; 3:e00123-18. [PMID: 30417115 PMCID: PMC6222046 DOI: 10.1128/msystems.00123-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/11/2018] [Indexed: 02/06/2023] Open
Abstract
The gut microbiota is susceptible to modulation by environmental stimuli and therefore can serve as a biological sensor. Recent evidence suggests that xenobiotics can disrupt the interaction between the microbiota and host. Here, we describe an approach that combines in vitro microbial incubation (isolated cecal contents from mice), flow cytometry, and mass spectrometry- and 1H nuclear magnetic resonance (NMR)-based metabolomics to evaluate xenobiotic-induced microbial toxicity. Tempol, a stabilized free radical scavenger known to remodel the microbial community structure and function in vivo, was studied to assess its direct effect on the gut microbiota. The microbiota was isolated from mouse cecum and was exposed to tempol for 4 h under strict anaerobic conditions. The flow cytometry data suggested that short-term tempol exposure to the microbiota is associated with disrupted membrane physiology as well as compromised metabolic activity. Mass spectrometry and NMR metabolomics revealed that tempol exposure significantly disrupted microbial metabolic activity, specifically indicated by changes in short-chain fatty acids, branched-chain amino acids, amino acids, nucleotides, glucose, and oligosaccharides. In addition, a mouse study with tempol (5 days gavage) showed similar microbial physiologic and metabolic changes, indicating that the in vitro approach reflected in vivo conditions. Our results, through evaluation of microbial viability, physiology, and metabolism and a comparison of in vitro and in vivo exposures with tempol, suggest that physiologic and metabolic phenotyping can provide unique insight into gut microbiota toxicity. IMPORTANCE The gut microbiota is modulated physiologically, compositionally, and metabolically by xenobiotics, potentially causing metabolic consequences to the host. We recently reported that tempol, a stabilized free radical nitroxide, can exert beneficial effects on the host through modulation of the microbiome community structure and function. Here, we investigated a multiplatform phenotyping approach that combines high-throughput global metabolomics with flow cytometry to evaluate the direct effect of tempol on the microbiota. This approach may be useful in deciphering how other xenobiotics directly influence the microbiota.
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Affiliation(s)
- Jingwei Cai
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Robert G. Nichols
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Imhoi Koo
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Zachary A. Kalikow
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Limin Zhang
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences (CAS), Wuhan, China
| | - Yuan Tian
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences (CAS), Wuhan, China
| | - Jingtao Zhang
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Philip B. Smith
- Metabolomics Facility, Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Andrew D. Patterson
- Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
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Huang TH, Tzeng YL, Dickson RM. FAST: Rapid determinations of antibiotic susceptibility phenotypes using label-free cytometry. Cytometry A 2018; 93:639-648. [PMID: 29733508 DOI: 10.1002/cyto.a.23370] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/25/2018] [Accepted: 03/15/2018] [Indexed: 11/08/2022]
Abstract
Sepsis, a life-threatening immune response to blood infections (bacteremia), has a ∼30% mortality rate and is the 10th leading cause of US hospital deaths. The typical bacterial loads in adult septic patients are ≤100 bacterial cells (colony forming units, CFU) per ml blood, while pediatric patients exhibit only ∼1000 CFU/ml. Due to the low numbers, bacteria must be propagated through ∼24-hours blood cultures to generate sufficient CFUs for diagnosis and further analyses. Herein, we demonstrate that, unlike other rapid post-blood culture antibiotic susceptibility tests (ASTs), our phenotypic approach can drastically accelerate ASTs for the most common sepsis-causing gram-negative pathogens by circumventing long blood culture-based amplification. For all blood isolates of multi-drug resistant pathogens investigated (Escherichia coli, Klebsiella pneumoniae, and Acinetobacter nosocomialis), effective antibiotic(s) were readily identified within the equivalent of 8 hours from initial blood draw using <0.5 mL of adult blood per antibiotic. These methods should drastically improve patient outcomes by significantly reducing time to actionable treatment information and reduce the incidence of antibiotic resistance. © 2018 International Society for Advancement of Cytometry.
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Affiliation(s)
- Tzu-Hsueh Huang
- School of Chemistry & Biochemistry and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400
| | - Yih-Ling Tzeng
- Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, 30322
| | - Robert M Dickson
- School of Chemistry & Biochemistry and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400
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Huang TH, Ning X, Wang X, Murthy N, Tzeng YL, Dickson RM. Rapid cytometric antibiotic susceptibility testing utilizing adaptive multidimensional statistical metrics. Anal Chem 2015; 87:1941-9. [PMID: 25540985 PMCID: PMC4317060 DOI: 10.1021/ac504241x] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
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Flow cytometry holds promise to accelerate
antibiotic susceptibility
determinations; however, without robust multidimensional statistical
analysis, general discrimination criteria have remained elusive. In
this study, a new statistical method, probability binning signature
quadratic form (PB-sQF), was developed and applied to analyze flow
cytometric data of bacterial responses to antibiotic exposure. Both
sensitive lab strains (Escherichia coli and Pseudomonas aeruginosa) and a multidrug resistant, clinically
isolated strain (E. coli) were incubated with the
bacteria-targeted dye, maltohexaose-conjugated IR786, and each of
many bactericidal or bacteriostatic antibiotics to identify changes
induced around corresponding minimum inhibition concentrations (MIC).
The antibiotic-induced damages were monitored by flow cytometry after
1-h incubation through forward scatter, side scatter, and fluorescence
channels. The 3-dimensional differences between the flow cytometric
data of the no-antibiotic treated bacteria and the antibiotic-treated
bacteria were characterized by PB-sQF into a 1-dimensional linear
distance. A 99% confidence level was established by statistical bootstrapping
for each antibiotic-bacteria pair. For the susceptible E.
coli strain, statistically significant increments from this
99% confidence level were observed from 1/16x MIC to 1x MIC for all
the antibiotics. The same increments were recorded for P.
aeruginosa, which has been reported to cause difficulty in
flow-based viability tests. For the multidrug resistant E.
coli, significant distances from control samples were observed
only when an effective antibiotic treatment was utilized. Our results
suggest that a rapid and robust antimicrobial susceptibility test
(AST) can be constructed by statistically characterizing the differences
between sample and control flow cytometric populations, even in a
label-free scheme with scattered light alone. These distances vs paired
controls coupled with rigorous statistical confidence limits offer
a new path toward investigating initial biological responses, screening
for drugs, and shortening time to result in antimicrobial sensitivity
testing.
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Affiliation(s)
- Tzu-Hsueh Huang
- School of Chemistry & Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology , Atlanta, Georgia 30305-0400, United States
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Applications of flow cytometry to characterize bacterial physiological responses. BIOMED RESEARCH INTERNATIONAL 2014; 2014:461941. [PMID: 25276788 PMCID: PMC4174974 DOI: 10.1155/2014/461941] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/13/2014] [Accepted: 08/13/2014] [Indexed: 12/30/2022]
Abstract
Although reports of flow cytometry (FCM) applied to bacterial analysis are increasing, studies of FCM related to human cells still vastly outnumber other reports. However, current advances in FCM combined with a new generation of cellular reporter probes have made this technique suitable for analyzing physiological responses in bacteria. We review how FCM has been applied to characterize distinct physiological conditions in bacteria including responses to antibiotics and other cytotoxic chemicals and physical factors, pathogen-host interactions, cell differentiation during biofilm formation, and the mechanisms governing development pathways such as sporulation. Since FCM is suitable for performing studies at the single-cell level, we describe how this powerful technique has yielded invaluable information about the heterogeneous distribution of differently and even specialized responding cells and how it may help to provide insights about how cell interaction takes place in complex structures, such as those that prevail in bacterial biofilms.
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Abstract
Ureaplasma species commonly colonize the adult urogenital tract and are implicated in invasive diseases of adults and neonates. Factors that permit the organisms to cause chronic colonization or infection are poorly understood. We sought to investigate whether host innate immune responses, specifically, antimicrobial peptides (AMPs), are involved in determining the outcome of Ureaplasma infections. THP-1 cells, a human monocytoid tumor line, were cocultured with Ureaplasma parvum and U. urealyticum. Gene expression levels of a variety of host defense genes were quantified by real-time PCR. In vitro antimicrobial activities of synthetic AMPs against Ureaplasma spp. were determined using a flow cytometry-based assay. Chromosomal histone modifications in host defense gene promoters were tested by chromatin immunoprecipitation (ChIP). DNA methylation status in the AMP promoter regions was also investigated. After stimulation with U. parvum and U. urealyticum, the expression of cell defense genes, including the AMP genes (DEFB1, DEFA5, DEFA6, and CAMP), was significantly downregulated compared to that of TNFA and IL-8, which were upregulated. In vitro flow cytometry-based antimicrobial assay revealed that synthetic peptides LL-37, hBD-3, and hBD-1 had activity against Ureaplasma spp. Downregulation of the AMP genes was associated with chromatin modification alterations, including the significantly decreased histone H3K9 acetylation with U. parvum infection. No DNA methylation status changes were detected upon Ureaplasma infection. In conclusion, AMPs have in vitro activity against Ureaplasma spp., and suppression of AMP expression might be important for the organisms to avoid this aspect of the host innate immune response and to establish chronic infection and colonization.
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