1
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Narayana Iyengar S, Dowden B, Ragheb K, Patsekin V, Rajwa B, Bae E, Robinson JP. Identifying antibiotic-resistant strains via cell sorting and elastic-light-scatter phenotyping. Appl Microbiol Biotechnol 2024; 108:406. [PMID: 38958764 PMCID: PMC11222266 DOI: 10.1007/s00253-024-13232-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/04/2024] [Accepted: 03/19/2024] [Indexed: 07/04/2024]
Abstract
The proliferation and dissemination of antimicrobial-resistant bacteria is an increasingly global challenge and is attributed mainly to the excessive or improper use of antibiotics. Currently, the gold-standard phenotypic methodology for detecting resistant strains is agar plating, which is a time-consuming process that involves multiple subculturing steps. Genotypic analysis techniques are fast, but they require pure starting samples and cannot differentiate between viable and non-viable organisms. Thus, there is a need to develop a better method to identify and prevent the spread of antimicrobial resistance. This work presents a novel method for detecting and identifying antibiotic-resistant strains by combining a cell sorter for bacterial detection and an elastic-light-scattering method for bacterial classification. The cell sorter was equipped with safety mechanisms for handling pathogenic organisms and enabled precise placement of individual bacteria onto an agar plate. The patterning was performed on an antibiotic-gradient plate, where the growth of colonies in sections with high antibiotic concentrations confirmed the presence of a resistant strain. The antibiotic-gradient plate was also tested with an elastic-light-scattering device where each colony's unique colony scatter pattern was recorded and classified using machine learning for rapid identification of bacteria. Sorting and patterning bacteria on an antibiotic-gradient plate using a cell sorter reduced the number of subculturing steps and allowed direct qualitative binary detection of resistant strains. Elastic-light-scattering technology is a rapid, label-free, and non-destructive method that permits instantaneous classification of pathogenic strains based on the unique bacterial colony scatter pattern. KEY POINTS: • Individual bacteria cells are placed on gradient agar plates by a cell sorter • Laser-light scatter patterns are used to recognize antibiotic-resistant organisms • Scatter patterns formed by colonies correspond to AMR-associated phenotypes.
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Affiliation(s)
| | - Brianna Dowden
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Kathy Ragheb
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Valery Patsekin
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Bartek Rajwa
- Bindley Bioscience Center, Purdue University, West Lafayette, IN, 47907, USA
| | - Euiwon Bae
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - J Paul Robinson
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, 47907, USA.
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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2
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Kasputis T, He Y, Ci Q, Chen J. On-Site Fluorescent Detection of Sepsis-Inducing Bacteria using a Graphene-Oxide CRISPR-Cas12a (GO-CRISPR) System. Anal Chem 2024; 96:2676-2683. [PMID: 38290431 PMCID: PMC10867801 DOI: 10.1021/acs.analchem.3c05459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/02/2024] [Accepted: 01/08/2024] [Indexed: 02/01/2024]
Abstract
Sepsis is an extremely dangerous medical condition that emanates from the body's response to a pre-existing infection. Early detection of sepsis-inducing bacterial infections can greatly enhance the treatment process and potentially prevent the onset of sepsis. However, current point-of-care (POC) sensors are often complex and costly or lack the ideal sensitivity for effective bacterial detection. Therefore, it is crucial to develop rapid and sensitive biosensors for the on-site detection of sepsis-inducing bacteria. Herein, we developed a graphene oxide CRISPR-Cas12a (GO-CRISPR) biosensor for the detection of sepsis-inducing bacteria in human serum. In this strategy, single-stranded (ssDNA) FAM probes were quenched with single-layer graphene oxide (GO). Target-activated Cas12a trans-cleavage was utilized for the degradation of the ssDNA probes, detaching the short ssDNA probes from GO and recovering the fluorescent signals. Under optimal conditions, we employed our GO-CRISPR system for the detection of Salmonella Typhimurium (S. Typhimurium) with a detection sensitivity of as low as 3 × 103 CFU/mL in human serum, as well as a good detection specificity toward other competing bacteria. In addition, the GO-CRISPR biosensor exhibited excellent sensitivity to the detection of S. Typhimurium in spiked human serum. The GO-CRISPR system offers superior rapidity for the detection of sepsis-inducing bacteria and has the potential to enhance the early detection of bacterial infections in resource-limited settings, expediting the response for patients at risk of sepsis.
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Affiliation(s)
- Tom Kasputis
- Department
of Biological Systems Engineering, Virginia
Tech, Blacksburg, Virginia 24061, United States
| | - Yawen He
- Department
of Biological Systems Engineering, Virginia
Tech, Blacksburg, Virginia 24061, United States
| | - Qiaoqiao Ci
- Department
of Biological Systems Engineering, Virginia
Tech, Blacksburg, Virginia 24061, United States
| | - Juhong Chen
- Department
of Biological Systems Engineering, Virginia
Tech, Blacksburg, Virginia 24061, United States
- Department
of Bioengineering, University of California, Riverside, California 92521, United States
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3
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Bhunia AK, Singh AK, Parker K, Applegate BM. Petri-plate, bacteria, and laser optical scattering sensor. Front Cell Infect Microbiol 2022; 12:1087074. [PMID: 36619754 PMCID: PMC9813400 DOI: 10.3389/fcimb.2022.1087074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
Classical microbiology has paved the path forward for the development of modern biotechnology and microbial biosensing platforms. Microbial culturing and isolation using the Petri plate revolutionized the field of microbiology. In 1887, Julius Richard Petri invented possibly the most important tool in microbiology, the Petri plate, which continues to have a profound impact not only on reliably isolating, identifying, and studying microorganisms but also manipulating a microbe to study gene expression, virulence properties, antibiotic resistance, and production of drugs, enzymes, and foods. Before the recent advances in gene sequencing, microbial identification for diagnosis relied upon the hierarchal testing of a pure culture isolate. Direct detection and identification of isolated bacterial colonies on a Petri plate with a sensing device has the potential for revolutionizing further development in microbiology including gene sequencing, pathogenicity study, antibiotic susceptibility testing , and for characterizing industrially beneficial traits. An optical scattering sensor designated BARDOT (bacterial rapid detection using optical scattering technology) that uses a red-diode laser, developed at the beginning of the 21st century at Purdue University, some 220 years after the Petri-plate discovery can identify and study bacteria directly on the plate as a diagnostic tool akin to Raman scattering and hyperspectral imaging systems for application in clinical and food microbiology laboratories.
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Affiliation(s)
- Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States,Purdue University, Purdue University Interdisciplinary Life Science Program (PULSe), West Lafayette, IN, United States,Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, United States,Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, United States,*Correspondence: Arun K. Bhunia,
| | - Atul K. Singh
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States,Clear Labs, San Carlos, CA, United States
| | - Kyle Parker
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
| | - Bruce M. Applegate
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States,Purdue University, Purdue University Interdisciplinary Life Science Program (PULSe), West Lafayette, IN, United States,Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, United States,Department of Biological Sciences, Purdue University, West Lafayette, IN, United States
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4
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Phillips SMB, Bergstrom C, Walker B, Wang G, Alfaro T, Stromberg ZR, Hess BM. Engineered Cell Line Imaging Assay Differentiates Pathogenic from Non-Pathogenic Bacteria. Pathogens 2022; 11:pathogens11020209. [PMID: 35215152 PMCID: PMC8874627 DOI: 10.3390/pathogens11020209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 01/27/2023] Open
Abstract
Cell culture systems have greatly expanded our understanding of how bacterial pathogens target signaling pathways to manipulate the host and cause infection. Advances in genetic engineering have allowed for the creation of fluorescent protein readouts within signaling pathways, but these techniques have been underutilized in pathogen biology. Here, we genetically engineered a lung cell line with fluorescent reporters for extracellular signal-related kinase (ERK) and the downstream transcription factor FOS-related antigen 1 (Fra1) and evaluated signaling after inoculation with pathogenic and non-pathogenic bacteria. Cells were inoculated with 100 colony-forming units of Acinetobacter baylyi, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus agalactiae, or Staphylococcus epidermidis and imaged in a multi-mode reader. The alamarBlue cell viability assay was used as a reference test and showed that pathogenic P. aeruginosa induced significant (p < 0.05) cell death after 8 h in both wild-type and engineered cell lines compared to non-pathogenic S. epidermidis. In engineered cells, we found that Fra1 signaling was disrupted in as little as 4 h after inoculation with bacterial pathogens compared to delayed disruption in signaling by non-pathogenic S. epidermidis. Overall, we demonstrate that low levels of pathogenic versus non-pathogenic bacteria can be rapidly and sensitively screened based on ERK-Fra1 signaling.
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5
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Advancement in Salmonella Detection Methods: From Conventional to Electrochemical-Based Sensing Detection. BIOSENSORS-BASEL 2021; 11:bios11090346. [PMID: 34562936 PMCID: PMC8468554 DOI: 10.3390/bios11090346] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/06/2021] [Accepted: 09/09/2021] [Indexed: 02/07/2023]
Abstract
Large-scale food-borne outbreaks caused by Salmonella are rarely seen nowadays, thanks to the advanced nature of the medical system. However, small, localised outbreaks in certain regions still exist and could possess a huge threat to the public health if eradication measure is not initiated. This review discusses the progress of Salmonella detection approaches covering their basic principles, characteristics, applications, and performances. Conventional Salmonella detection is usually performed using a culture-based method, which is time-consuming, labour intensive, and unsuitable for on-site testing and high-throughput analysis. To date, there are many detection methods with a unique detection system available for Salmonella detection utilising immunological-based techniques, molecular-based techniques, mass spectrometry, spectroscopy, optical phenotyping, and biosensor methods. The electrochemical biosensor has growing interest in Salmonella detection mainly due to its excellent sensitivity, rapidity, and portability. The use of a highly specific bioreceptor, such as aptamers, and the application of nanomaterials are contributing factors to these excellent characteristics. Furthermore, insight on the types of biorecognition elements, the principles of electrochemical transduction elements, and the miniaturisation potential of electrochemical biosensors are discussed.
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6
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Xu L, Bai X, Bhunia AK. Current State of Development of Biosensors and Their Application in Foodborne Pathogen Detection. J Food Prot 2021; 84:1213-1227. [PMID: 33710346 DOI: 10.4315/jfp-20-464] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 03/11/2021] [Indexed: 01/16/2023]
Abstract
ABSTRACT Foodborne disease outbreaks continue to be a major public health and food safety concern. Testing products promptly can protect consumers from foodborne diseases by ensuring the safety of food before retail distribution. Fast, sensitive, and accurate detection tools are in great demand. Therefore, various approaches have been explored recently to find a more effective way to incorporate antibodies, oligonucleotides, phages, and mammalian cells as signal transducers and analyte recognition probes on biosensor platforms. The ultimate goal is to achieve high specificity and low detection limits (1 to 100 bacterial cells or piconanogram concentrations of toxins). Advancements in mammalian cell-based and bacteriophage-based sensors have produced sensors that detect low levels of pathogens and differentiate live from dead cells. Combinations of biotechnology platforms have increased the practical utility and application of biosensors for detection of foodborne pathogens. However, further rigorous testing of biosensors with complex food matrices is needed to ensure the utility of these sensors for point-of-care needs and outbreak investigations. HIGHLIGHTS
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Affiliation(s)
- Luping Xu
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana 47907, USA
| | - Xingjian Bai
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana 47907, USA
| | - Arun K Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana 47907, USA.,Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana 47907, USA.,Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, USA
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7
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Xu L, Bai X, Tenguria S, Liu Y, Drolia R, Bhunia AK. Mammalian Cell-Based Immunoassay for Detection of Viable Bacterial Pathogens. Front Microbiol 2020; 11:575615. [PMID: 33329436 PMCID: PMC7732435 DOI: 10.3389/fmicb.2020.575615] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 10/29/2020] [Indexed: 12/24/2022] Open
Abstract
Rapid detection of live pathogens is of paramount importance to ensure food safety. At present, nucleic acid-based polymerase chain reaction and antibody-based lateral flow assays are the primary methods of choice for rapid detection, but these are prone to interference from inhibitors, and resident microbes. Moreover, the positive results may neither assure virulence potential nor viability of the analyte. In contrast, the mammalian cell-based assay detects pathogen interaction with the host cells and is responsive to only live pathogens, but the short shelf-life of the mammalian cells is the major impediment for its widespread application. An innovative approach to prolong the shelf-life of mammalian cells by using formalin was undertaken. Formalin (4% formaldehyde)-fixed human ileocecal adenocarcinoma cell line, HCT-8 on 24-well tissue culture plates was used for the capture of viable pathogens while an antibody was used for specific detection. The specificity of the Mammalian Cell-based ImmunoAssay (MaCIA) was validated with Salmonella enterica serovar Enteritidis and Typhimurium as model pathogens and further confirmed against a panel of 15 S. Enteritidis strains, 8 S. Typhimurium, 11 other Salmonella serovars, and 14 non-Salmonella spp. The total detection time (sample-to-result) of MaCIA with artificially inoculated ground chicken, eggs, milk, and cake mix at 1-10 CFU/25 g was 16-21 h using a traditional enrichment set up but the detection time was shortened to 10-12 h using direct on-cell (MaCIA) enrichment. Formalin-fixed stable cell monolayers in MaCIA provide longer shelf-life (at least 14 weeks) for possible point-of-need deployment and multi-sample testing on a single plate.
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Affiliation(s)
- Luping Xu
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Xingjian Bai
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Shivendra Tenguria
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Yi Liu
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Rishi Drolia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, United States
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, United States
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, United States
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8
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Locke A, Fitzgerald S, Mahadevan-Jansen A. Advances in Optical Detection of Human-Associated Pathogenic Bacteria. Molecules 2020; 25:E5256. [PMID: 33187331 PMCID: PMC7696695 DOI: 10.3390/molecules25225256] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 02/06/2023] Open
Abstract
Bacterial infection is a global burden that results in numerous hospital visits and deaths annually. The rise of multi-drug resistant bacteria has dramatically increased this burden. Therefore, there is a clinical need to detect and identify bacteria rapidly and accurately in their native state or a culture-free environment. Current diagnostic techniques lack speed and effectiveness in detecting bacteria that are culture-negative, as well as options for in vivo detection. The optical detection of bacteria offers the potential to overcome these obstacles by providing various platforms that can detect bacteria rapidly, with minimum sample preparation, and, in some cases, culture-free directly from patient fluids or even in vivo. These modalities include infrared, Raman, and fluorescence spectroscopy, along with optical coherence tomography, interference, polarization, and laser speckle. However, these techniques are not without their own set of limitations. This review summarizes the strengths and weaknesses of utilizing each of these optical tools for rapid bacteria detection and identification.
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Affiliation(s)
- Andrea Locke
- Vanderbilt Biophotonics Center, Nashville, TN 37232, USA; (A.L.); (S.F.)
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
| | - Sean Fitzgerald
- Vanderbilt Biophotonics Center, Nashville, TN 37232, USA; (A.L.); (S.F.)
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
| | - Anita Mahadevan-Jansen
- Vanderbilt Biophotonics Center, Nashville, TN 37232, USA; (A.L.); (S.F.)
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
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9
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Lee J, Lee SY, Han S, Seong D, Wijesinghe RE, Kim P, Jeon M, Jung HY, Kim J. Multi-directional Morphological Assessment of Single Bacterial Colonies Through Non-invasive Optical Imaging. Ann Biomed Eng 2020; 48:3014-3023. [PMID: 33118064 DOI: 10.1007/s10439-020-02660-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/12/2020] [Indexed: 11/28/2022]
Abstract
A bacterium in bacterial colony is a basal component of bacterial studies and is therefore of considerable importance. The morphological characteristics of a single colony have been widely used as the standard to identify diverse bacterial species. However, the conventional methods for obtaining morphological information, such as microscopic techniques, cannot provide tomographic views. This study utilizes spectral-domain optical coherence tomography (SD-OCT) to observe both external and internal structures for single colonies. OCT imaging provided a clear top (projection) and lateral (cross-sectional) images, which can identify distinct features in the fifteen different bacterial species examined. Through the acquired OCT images, the elevation type in each genus was confirmed, and the quantitative measurements for morphology including a diameter, height, and elevation angle were achieved. Moreover, the OCT raw data was used to build three-dimensional images to observe outer appearances in all direction. As a result, the averaged angles of 7.92°, 14.40°, 6.78°, and 11.92° of the genus Hymenobacter, Spirosoma, Bacillus, and Deinococcus, respectively, were calculated. In conclusion, we have demonstrated that OCT is a highly feasible, non-invasive method for the identification of bacterial species, providing detailed morphological and visual information. It thus has strong potential for applications in bacteriology, as well as biomedical and food sciences.
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Affiliation(s)
- Junsoo Lee
- School of Electronic and Electrical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Taegu, 41566, South Korea
| | - Seung-Yeol Lee
- School of Applied Biosciences, Kyungpook National University, 80 Daehak-ro, Buk-gu, Taegu, 41566, South Korea
| | - Sangyeob Han
- School of Electronic and Electrical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Taegu, 41566, South Korea
| | - Daewoon Seong
- School of Electronic and Electrical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Taegu, 41566, South Korea
| | - Ruchire Eranga Wijesinghe
- Department of Biomedical Engineering, Kyungil University, 50 Gamasil-gil, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do, 38428, South Korea
| | - Pilun Kim
- School of Medicine, Kyungpook National University, 80 Daehak-ro, Buk-gu, Taegu, 41566, South Korea
| | - Mansik Jeon
- School of Electronic and Electrical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Taegu, 41566, South Korea
| | - Hee-Young Jung
- School of Applied Biosciences, Kyungpook National University, 80 Daehak-ro, Buk-gu, Taegu, 41566, South Korea.
| | - Jeehyun Kim
- School of Electronic and Electrical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Taegu, 41566, South Korea.
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10
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Doh IJ, Sturgis J, Sarria Zuniga DV, Pruitt RE, Robinson JP, Bae E. Generalized spectral light scatter models of diverse bacterial colony morphologies. JOURNAL OF BIOPHOTONICS 2019; 12:e201900149. [PMID: 31386275 DOI: 10.1002/jbio.201900149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/03/2019] [Accepted: 08/04/2019] [Indexed: 06/10/2023]
Abstract
An optical forward-scatter model was generalized to encompass the diverse nature of bacterial colony morphologies and the spectral information. According to the model, the colony shape and the wavelength of incident light significantly affect the characteristics of a forward elastic-light-scattering pattern. To study the relationship between the colony morphology and the scattering pattern, three-dimensional colony models were generated in various morphologies. The propagation of light passing through the colony model was then simulated. In validation of the theoretical modeling, the scattering patterns of three bacterial genera, Staphylococcus, Exiguobacterium and Bacillus, which grow into colonies having convex, crateriform and flat elevations, respectively, were qualitatively compared to the simulated scattering patterns. The strong correlations observed between simulated and experimental patterns validated the scatter model. In addition, spectral effect on the scattering pattern was studied using the scatter model, and experimentally investigated using Staphylococcus, whose colony has circular form and convex elevation. Both simulation and experiment showed that changes in wavelength affected the overall pattern size and the number of rings.
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Affiliation(s)
- Iyll-Joon Doh
- Applied Optics Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, Indiana
| | - Jennifer Sturgis
- Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana
| | | | - Robert E Pruitt
- Botany and Plant Pathology, Purdue University, West Lafayette, Indiana
| | - J Paul Robinson
- Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
| | - Euiwon Bae
- Applied Optics Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, Indiana
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11
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Abdelhaseib MU, Singh AK, Bhunia AK. Simultaneous detection of Salmonella enterica, Escherichia coli and Listeria monocytogenes in food using a light scattering sensor. J Appl Microbiol 2019; 126:1496-1507. [PMID: 30761711 DOI: 10.1111/jam.14225] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 02/04/2019] [Accepted: 02/11/2019] [Indexed: 12/13/2022]
Abstract
AIM To investigate the use of a light scattering sensor, BActerial Rapid Detection using Optical scattering Technology (BARDOT) coupled with a multipathogen selective medium, Salmonella, Escherichia and Listeria (SEL), for concurrent detection of the three major foodborne pathogens in a single assay. METHODS AND RESULTS BARDOT was used to detect and distinguish the three major pathogens, Salmonella enterica, Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes from food based on colony scatter signature patterns on SEL agar (SELA). Multiple strains of three test pathogens were grown on SELA, and BARDOT was used to generate colony scatter image libraries for inclusive (SEL Library) and exclusive (non-SEL Library) bacterial group. These pathogens were further differentiated using the SEL scatter image library. Raw chicken and hotdog samples were artificially inoculated with pathogens (100 CFU per 25 g each), and enriched in SEL broth at 37°C for 18 h and colonies were grown on SELA for 11-22 h before screening with BARDOT. The BARDOT sensor successfully detected and differentiated Salmonella, STEC and Listeria on SELA with high classification accuracy 92-98%, 91-98% and 83-98% positive predictive values (PPV) respectively; whereas the nontarget strains showed only 0-13% PPV. BARDOT-identified colonies were further confirmed by multiplex PCR targeting inlB gene of L. monocytogenes, stx2 of STEC and sefA of S. enterica serovar Enteritidis. CONCLUSIONS The results show that BARDOT coupled with SELA can efficiently screen for the presence of three major pathogens simultaneously in a test sample within 29-40 h. SIGNIFICANCE AND IMPACT OF THE STUDY This innovative SELA-BARDOT detection platform can reduce turnaround time and economic burden on food industries by offering a label-free, noninvasive on-plate multipathogen screening technology for reducing microbial food safety and public health concerns.
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Affiliation(s)
- M U Abdelhaseib
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, USA.,Food Hygiene Department, Assiut University, Assiut, Egypt
| | - A K Singh
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, USA.,Clear Labs, Menlo Park, CA, USA
| | - A K Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, USA.,Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, USA.,Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA
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12
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Walper SA, Lasarte Aragonés G, Sapsford KE, Brown CW, Rowland CE, Breger JC, Medintz IL. Detecting Biothreat Agents: From Current Diagnostics to Developing Sensor Technologies. ACS Sens 2018; 3:1894-2024. [PMID: 30080029 DOI: 10.1021/acssensors.8b00420] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Although a fundamental understanding of the pathogenicity of most biothreat agents has been elucidated and available treatments have increased substantially over the past decades, they still represent a significant public health threat in this age of (bio)terrorism, indiscriminate warfare, pollution, climate change, unchecked population growth, and globalization. The key step to almost all prevention, protection, prophylaxis, post-exposure treatment, and mitigation of any bioagent is early detection. Here, we review available methods for detecting bioagents including pathogenic bacteria and viruses along with their toxins. An introduction placing this subject in the historical context of previous naturally occurring outbreaks and efforts to weaponize selected agents is first provided along with definitions and relevant considerations. An overview of the detection technologies that find use in this endeavor along with how they provide data or transduce signal within a sensing configuration follows. Current "gold" standards for biothreat detection/diagnostics along with a listing of relevant FDA approved in vitro diagnostic devices is then discussed to provide an overview of the current state of the art. Given the 2014 outbreak of Ebola virus in Western Africa and the recent 2016 spread of Zika virus in the Americas, discussion of what constitutes a public health emergency and how new in vitro diagnostic devices are authorized for emergency use in the U.S. are also included. The majority of the Review is then subdivided around the sensing of bacterial, viral, and toxin biothreats with each including an overview of the major agents in that class, a detailed cross-section of different sensing methods in development based on assay format or analytical technique, and some discussion of related microfluidic lab-on-a-chip/point-of-care devices. Finally, an outlook is given on how this field will develop from the perspective of the biosensing technology itself and the new emerging threats they may face.
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Affiliation(s)
- Scott A. Walper
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Guillermo Lasarte Aragonés
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
- College of Science, George Mason University Fairfax, Virginia 22030, United States
| | - Kim E. Sapsford
- OMPT/CDRH/OIR/DMD Bacterial Respiratory and Medical Countermeasures Branch, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Carl W. Brown
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
- College of Science, George Mason University Fairfax, Virginia 22030, United States
| | - Clare E. Rowland
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
- National Research Council, Washington, D.C. 20036, United States
| | - Joyce C. Breger
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Igor L. Medintz
- Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
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Zhu X, Liu D, Singh AK, Drolia R, Bai X, Tenguria S, Bhunia AK. Tunicamycin Mediated Inhibition of Wall Teichoic Acid Affects Staphylococcus aureus and Listeria monocytogenes Cell Morphology, Biofilm Formation and Virulence. Front Microbiol 2018; 9:1352. [PMID: 30034372 PMCID: PMC6043806 DOI: 10.3389/fmicb.2018.01352] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/05/2018] [Indexed: 12/14/2022] Open
Abstract
The emergence of bacterial resistance to therapeutic antibiotics limits options for treatment of common microbial diseases. Subinhibitory antibiotics dosing, often aid in the emergence of resistance, but its impact on pathogen’s physiology and pathogenesis is not well understood. Here we investigated the effect of tunicamycin, a cell wall teichoic acid (WTA) biosynthesis inhibiting antibiotic at the subinhibitory dosage on Staphylococcus aureus and Listeria monocytogenes physiology, antibiotic cross-resistance, biofilm-formation, and virulence. Minimum inhibitory concentration (MIC) of tunicamycin to S. aureus and L. monocytogenes was 20–40 μg/ml and 2.5–5 μg/ml, respectively, and the subinhibitory concentration was 2.5–5 μg/ml and 0.31–0.62 μg/ml, respectively. Tunicamycin pre-exposure reduced cellular WTA levels by 18–20% and affected bacterial cell wall ultrastructure, cell membrane permeability, morphology, laser-induced colony scatter signature, and bacterial ability to form biofilms. It also induced a moderate level of cross-resistance to tetracycline, ampicillin, erythromycin, and meropenem for S. aureus, and ampicillin, erythromycin, vancomycin, and meropenem for L. monocytogenes. Pre-treatment of bacterial cells with subinhibitory concentrations of tunicamycin also significantly reduced bacterial adhesion to and invasion into an enterocyte-like Caco-2 cell line, which is supported by reduced expression of key virulence factors, Internalin B (InlB) and Listeria adhesion protein (LAP) in L. monocytogenes, and a S. aureus surface protein A (SasA) in S. aureus. Tunicamycin-treated bacteria or the bacterial WTA preparation suppressed NF-κB and inflammatory cytokine production (TNFα, and IL-6) from murine macrophage cell line (RAW 264.7) indicating the reduced WTA level possibly attenuates an inflammatory response. These results suggest that at the subinhibitory dosage, tunicamycin-mediated inhibition of WTA biosynthesis interferes with cell wall structure, pathogens infectivity and inflammatory response, and ability to form biofilms but promotes the development of antibiotic cross-resistance.
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Affiliation(s)
- Xingyue Zhu
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States.,College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing, China
| | - Dongqi Liu
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Atul K Singh
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Rishi Drolia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Xingjian Bai
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Shivendra Tenguria
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Arun K Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States.,Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, United States
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Alsulami TS, Zhu X, Abdelhaseib MU, Singh AK, Bhunia AK. Rapid detection and differentiation of Staphylococcus colonies using an optical scattering technology. Anal Bioanal Chem 2018; 410:5445-5454. [DOI: 10.1007/s00216-018-1133-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/23/2018] [Accepted: 05/07/2018] [Indexed: 02/08/2023]
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15
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Recent trends in the development of complementary metal oxide semiconductor image sensors to detect foodborne bacterial pathogens. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2017.10.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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16
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Sweeney RE, Yoon JY. Angular photodiode array-based device to detect bacterial pathogens in a wound model. IEEE SENSORS JOURNAL 2017; 17:6911-6917. [PMID: 29430214 PMCID: PMC5802419 DOI: 10.1109/jsen.2017.2752155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We have developed a device that is able to rapidly and specifically diagnose bacterial pathogens in a wound model based on Mie scatter spectra from a tissue surface. The Mie scatter spectra collected is defined as the intensity of Mie scatter over the angle of detection from a tissue surface. A 650 nm LED perpendicular to the surface illuminates a tissue sample (90°) and photodiodes positioned in 10° increments from 10° to 80° of backscatter act as the detectors to collect these Mie scatter spectra. Through principal component analysis of the Mie scatter spectra collected, we have shown significant differences between Mie scatter spectra of tissues with bacterial pathogens versus those without, as well as significant differences between each species of bacteria tested. The device developed has been tested with a porcine dermis wound model, with samples inoculated with one of three bacterial species (Staphylococcus aureus, Escherichia coli, or Salmonella Typhimurium). Such a device could be critical in the monitoring of a wound for infection and rapid, specific diagnosis of a bacterial wound infection, which would significantly reduce the time and cost associated with specific diagnosis of a bacterial wound infection currently.
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Affiliation(s)
- Robin E Sweeney
- Department of Biomedical Engineering at the University of Arizona, Tucson, AZ 85721, USA
| | - Jeong-Yeol Yoon
- Department of Biomedical Engineering at the University of Arizona, Tucson, AZ 85721, USA
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17
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Mie scatter spectra-based device for instant, contact-free, and specific diagnosis of bacterial skin infection. Sci Rep 2017; 7:4801. [PMID: 28684745 PMCID: PMC5500527 DOI: 10.1038/s41598-017-05061-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 05/23/2017] [Indexed: 12/21/2022] Open
Abstract
Rapid and specific diagnostic techniques are needed to expedite specific treatment of bacterial skin infections with narrow-spectrum antibiotics, rather than broad-spectrum. Through this work a device was developed to determine the presence of and species responsible for a bacterial skin infection using differences in Mie scatter spectra created by different bacterial species. A 650 nm LED at five different incident angles is used to illuminate the tissue, with Mie scatter being detected by PIN photodiodes at eight different detection angles. Mie scatter patterns are collected at all photodiode angles for each of the incident light angles, resulting in a Mie scatter spectra. Detectable differences in Mie scatter spectra were found using the device developed between commensal bacteria (no infection) and bacteria inoculated (infection) on the surface of both porcine and human cadaveric epidermis. Detectable differences were found between species of infection, specifically Escherichia coli and Staphylococcus aureus, with differences summarized through principle component analysis. Mie scatter spectra can be detected within a few seconds without skin contact. This device is the first to rapidly and specifically diagnose bacterial skin infections in a contact-less manner, allowing for initial treatment with narrow spectrum antibiotics, and helping to reduce the likelihood of resistance.
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Kim H, Rajwa B, Bhunia AK, Robinson JP, Bae E. Development of a multispectral light-scatter sensor for bacterial colonies. JOURNAL OF BIOPHOTONICS 2017; 10:634-644. [PMID: 27412151 DOI: 10.1002/jbio.201500338] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 05/16/2016] [Accepted: 06/01/2016] [Indexed: 06/06/2023]
Abstract
We report a multispectral elastic-light-scatter instrument that can simultaneously detect three-wavelength scatter patterns and associated optical densities from individual bacterial colonies, overcoming the limits of the single-wavelength predecessor. Absorption measurements on liquid bacterial samples revealed that the spectroscopic information can indeed contribute to sample differentiability. New optical components, including a pellicle beam splitter and an optical cage system, were utilized for robust acquisition of multispectral images. Four different genera and seven shiga toxin producing E. coli serovars were analyzed; the acquired images showed differences in scattering characteristics among the tested organisms. In addition, colony-based spectral optical-density information was also collected. The optical model, which was developed using diffraction theory, correctly predicted wavelength-related differences in scatter patterns, and was matched with the experimental results. Scatter-pattern classification was performed using pseudo-Zernike (GPZ) polynomials/moments by combining the features collected at all three wavelengths and selecting the best features via a random-forest method. The data demonstrate that the selected features provide better classification rates than the same number of features from any single wavelength. Three wavelength-merged scatter pattern from E. coli.
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Affiliation(s)
- Huisung Kim
- Applied Optics Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Bartek Rajwa
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN 47907, USA
- Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA
| | - Arun K Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN 47907, USA
| | - J Paul Robinson
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN 47907, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Euiwon Bae
- Applied Optics Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA
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Kim H, Doh IJ, Sturgis J, Bhunia AK, Robinson JP, Bae E. Reflected scatterometry for noninvasive interrogation of bacterial colonies. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:107004. [PMID: 27775748 DOI: 10.1117/1.jbo.21.10.107004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 10/06/2016] [Indexed: 06/06/2023]
Abstract
A phenotyping of bacterial colonies on agar plates using forward-scattering diffraction-pattern analysis provided promising classification of several different bacteria such as Salmonella, Vibrio, Listeria, and E. coli. Since the technique is based on forward-scattering phenomena, light transmittance of both the colony and the medium is critical to ensure quality data. However, numerous microorganisms and their growth media allow only limited light penetration and render the forward-scattering measurement a challenging task. For example, yeast, Lactobacillus, mold, and several soil bacteria form colorful and dense colonies that obstruct most of the incoming light passing through them. Moreover, blood agar, which is widely utilized in the clinical field, completely blocks the incident coherent light source used in forward scatterometry. We present a newly designed reflection scatterometer and validation of the resolving power of the instrument. The reflectance-type instrument can acquire backward elastic scatter patterns for both highly opaque media and colonies and has been tested with three different bacterial genera grown on blood agar plates. Cross-validation results show a classification rate above 90% for four genera.
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Affiliation(s)
- Huisung Kim
- Purdue University, School of Mechanical Engineering, Applied Optics Laboratory, West Lafayette, Indiana 47907, United States
| | - Iyll-Joon Doh
- Purdue University, School of Mechanical Engineering, Applied Optics Laboratory, West Lafayette, Indiana 47907, United States
| | - Jennifer Sturgis
- Purdue University, Department of Basic Medical Sciences, West Lafayette, Indiana 47907, United States
| | - Arun K Bhunia
- Purdue University, Molecular Food Microbiology Laboratory, Department of Food Science, West Lafayette, Indiana 47907, United States
| | - J Paul Robinson
- Purdue University, Department of Basic Medical Sciences, West Lafayette, Indiana 47907, United StatesdPurdue University, Weldon School of Biomedical Engineering, West Lafayette, Indiana 47907, United States
| | - Euiwon Bae
- Purdue University, School of Mechanical Engineering, Applied Optics Laboratory, West Lafayette, Indiana 47907, United States
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Myer PR, Parker KR, Kanach AT, Zhu T, Morgan MT, Applegate BM. The effect of a novel low temperature-short time (LTST) process to extend the shelf-life of fluid milk. SPRINGERPLUS 2016; 5:660. [PMID: 27350902 PMCID: PMC4899401 DOI: 10.1186/s40064-016-2250-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 04/28/2016] [Indexed: 11/12/2022]
Abstract
Pasteurization has long been the standard method to extend the shelf-life of dairy products, as well as a means to reduce microbial load and the risk of food-borne pathogens. However, the process has limitations, which include cost effectiveness, high energy input, and reduction of product quality/organoleptic characteristics. In an effort to reduce these limitations and extend shelf-life, this study examined a novel low temperature, short time (LTST) method in which dispersed milk in the form of droplets was treated with low heat/pressure variation over a short treatment time, in conjunction with pasteurization. Lactobacillus fermentum and Pseudomonas fluorescens Migula were exposed to conventional pasteurization treatments with and without LTST. Using these organisms, the LTST addition was able to reduce microbial load below detection limits; 1.0 × 101 cfu/mL, from approximately 1.2 × 108 and 1.0 × 107 cfu/mL for L. fermentum and P. fluorescens Migula, respectively. In addition, the shelf-life of the treated, raw, and uninoculated product was prolonged from 14 to 35 days, compared with standard pasteurization, to as long as 63 days with the LTST amendment. Sensory analysis of samples also demonstrated equal or greater preference for LTST + pasteurization treated milk when compared to pasteurization alone (α = 0.05). Conventional pasteurization was effective at reducing the above mentioned microorganisms by as much as 5.0 log10 cfu/mL. However, LTST was able to achieve 7.0–8.0 log10 cfu/mL reduction of the same microorganisms. In addition, BActerial Rapid Detection using Optical scattering Technology detected and identified microorganisms isolated both pre- and post-treatment, of which the only organisms surviving LTST were Bacillus spp. Increased lethality, improved shelf-life, and equal or better organoleptic characteristics without increased energy consumption demonstrate the effectiveness of the incorporation of LTST. The improved shelf-life may potentially have major impacts in the dairy industry in terms of shipping and overall sustainability.
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Affiliation(s)
- Phillip R Myer
- Department of Animal Science, University of Tennessee, Knoxville, TN 37996 USA
| | - Kyle R Parker
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-2054 USA
| | - Andrew T Kanach
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-2054 USA
| | - Tengliang Zhu
- Department of Food Science, Purdue University, West Lafayette, IN 47907-2009 USA
| | - Mark T Morgan
- Food Science and Technology Department, University of Tennessee, Knoxville, TN 37996 USA
| | - Bruce M Applegate
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-2054 USA ; Department of Food Science, Purdue University, West Lafayette, IN 47907-2009 USA
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Virulence Gene-Associated Mutant Bacterial Colonies Generate Differentiating Two-Dimensional Laser Scatter Fingerprints. Appl Environ Microbiol 2016; 82:3256-3268. [PMID: 26994085 DOI: 10.1128/aem.04129-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 03/16/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED In this study, we investigated whether a laser scatterometer designated BARDOT (bacterial rapid detection using optical scattering technology) could be used to directly screen colonies of Listeria monocytogenes, a model pathogen, with mutations in several known virulence genes, including the genes encoding Listeria adhesion protein (LAP; lap mutant), internalin A (ΔinlA strain), and an accessory secretory protein (ΔsecA2 strain). Here we show that the scatter patterns of lap mutant, ΔinlA, and ΔsecA2 colonies were markedly different from that of the wild type (WT), with >95% positive predictive values (PPVs), whereas for the complemented mutant strains, scatter patterns were restored to that of the WT. The scatter image library successfully distinguished the lap mutant and ΔinlA mutant strains from the WT in mixed-culture experiments, including a coinfection study using the Caco-2 cell line. Among the biophysical parameters examined, the colony height and optical density did not reveal any discernible differences between the mutant and WT strains. We also found that differential LAP expression in L. monocytogenes serotype 4b strains also affected the scatter patterns of the colonies. The results from this study suggest that BARDOT can be used to screen and enumerate mutant strains separately from the WT based on differential colony scatter patterns. IMPORTANCE In studies of microbial pathogenesis, virulence-encoding genes are routinely disrupted by deletion or insertion to create mutant strains. Screening of mutant strains is an arduous process involving plating on selective growth media, replica plating, colony hybridization, DNA isolation, and PCR or immunoassays. We applied a noninvasive laser scatterometer to differentiate mutant bacterial colonies from WT colonies based on forward optical scatter patterns. This study demonstrates that BARDOT can be used as a novel, label-free, real-time tool to aid researchers in screening virulence gene-associated mutant colonies during microbial pathogenesis, coinfection, and genetic manipulation studies.
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Rahman UU, Shahzad T, Sahar A, Ishaq A, Khan MI, Zahoor T, Aslam S. Recapitulating the competence of novel & rapid monitoring tools for microbial documentation in food systems. Lebensm Wiss Technol 2016. [DOI: 10.1016/j.lwt.2015.11.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Abdelhaseib MU, Singh AK, Bailey M, Singh M, El-Khateib T, Bhunia AK. Fiber optic and light scattering sensors: Complimentary approaches to rapid detection of Salmonella enterica in food samples. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.09.031] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Singh AK, Bhunia AK. Optical scatter patterns facilitate rapid differentiation of Enterobacteriaceae on CHROMagar™ Orientation medium. Microb Biotechnol 2016; 9:127-35. [PMID: 26503189 PMCID: PMC4720409 DOI: 10.1111/1751-7915.12323] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/27/2015] [Accepted: 08/28/2015] [Indexed: 12/01/2022] Open
Abstract
Enterobacteriaceae family comprised pathogens and commensals and has a significant impact on food safety and public health. Enterobacteriaceae is often enumerated and presumptively identified on chromogenic media, such as CHROMagar(TM) Orientation medium based on colony profile; however, classification is highly arbitrary, and some could not be differentiated due to similar chromogen production. Here, we investigated the ability of the laser optical sensor, BARDOT (bacterial rapid detection using optical scattering technology) for rapid screening and differentiation of colonies of the major bacterial genera from Enterobacteriaceae on CHROMagar(TM) Orientation. A total of 36 strains representing 12 genera and 15 species were used to generate colony scatter image library that comprised 1683 scatter images. This library was used to differentiate mixed cultures of Enterobacteriaceae family - Klebsiella pneumoniae, Enterobacter spp., Citrobacter freundii and Serratia marcescens (KECS group); Proteus mirabilis, Morganella morganii and Providencia rettgeri (PMP group); and non-Enterobacteriaceae family: Pseudomonas aeruginosa, Acinetobacter spp. and Staphylococcus aureus (PAS group) - and data show high accuracy (83-100%) for intra-group classification of colonies in 10-22 h or even before visible production of chromogens. BARDOT successfully differentiated the major genera, including the ones that do not produce visually distinguishable chromogens on CHROMagar(TM) Orientation, providing a label-free, real-time on-plate colony screening tool for Enterobacteriaceae.
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Affiliation(s)
- Atul K Singh
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, IN, 47907, USA
| | - Arun K Bhunia
- Department of Food Science, Molecular Food Microbiology Laboratory, Purdue University, West Lafayette, IN, 47907, USA
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, 47907, USA
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Bae E, Kim H, Rajwa B, Thomas JG, Robinson JP. Current status and future prospects of using advanced computer-based methods to study bacterial colonial morphology. Expert Rev Anti Infect Ther 2015; 14:207-18. [PMID: 26582139 DOI: 10.1586/14787210.2016.1122524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Despite the advancement of recent molecular technologies, culturing is still considered the gold standard for microbial sample analysis. Here we review three different bacterial colony-based screening modalities that provide significant information beyond the simple shape and color of the colony. The plate imaging technique provides numeration and quantitative spectral reflectance information for each colony, while Raman spectroscopic analysis of bacteria colonies relates the Raman-shifted peaks to specific chemical bonding. Finally, the elastic-light-scatter technique provides a volumetric interaction of the whole colony through laser-bacteria interactions, instantly capturing the morphological traits of the colony and allowing quantitative classifications.
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Affiliation(s)
- Euiwon Bae
- a School of Mechanical Engineering , Purdue University , West Lafayette , IN , USA
| | - Huisung Kim
- a School of Mechanical Engineering , Purdue University , West Lafayette , IN , USA
| | - Bartek Rajwa
- b Bindley Bioscience Center , Purdue University , West Lafayette , IN , USA
| | - John G Thomas
- c Microbiology Laboratory, Department of Laboratory Medicine , Allegheny Health Network , Pittsburgh , PA , USA
| | - J Paul Robinson
- d School of Veterinary Medicine , Purdue University , West Lafayette , IN , USA.,e Weldon School of Biomedical Engineering , Purdue University , West Lafayette , IN , USA
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Hahm BK, Kim H, Singh AK, Bhunia AK. Pathogen enrichment device (PED) enables one-step growth, enrichment and separation of pathogen from food matrices for detection using bioanalytical platforms. J Microbiol Methods 2015. [DOI: 10.1016/j.mimet.2015.07.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Novel PCR Assays Complement Laser Biosensor-Based Method and Facilitate Listeria Species Detection from Food. SENSORS 2015; 15:22672-91. [PMID: 26371000 PMCID: PMC4610479 DOI: 10.3390/s150922672] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 09/01/2015] [Indexed: 11/17/2022]
Abstract
The goal of this study was to develop the Listeria species-specific PCR assays based on a house-keeping gene (lmo1634) encoding alcohol acetaldehyde dehydrogenase (Aad), previously designated as Listeria adhesion protein (LAP), and compare results with a label-free light scattering sensor, BARDOT (bacterial rapid detection using optical scattering technology). PCR primer sets targeting the lap genes from the species of Listeria sensu stricto were designed and tested with 47 Listeria and 8 non-Listeria strains. The resulting PCR primer sets detected either all species of Listeria sensu stricto or individual L. innocua, L. ivanovii and L. seeligeri, L. welshimeri, and L. marthii without producing any amplified products from other bacteria tested. The PCR assays with Listeria sensu stricto-specific primers also successfully detected all species of Listeria sensu stricto and/or Listeria innocua from mixed culture-inoculated food samples, and each bacterium in food was verified by using the light scattering sensor that generated unique scatter signature for each species of Listeria tested. The PCR assays based on the house-keeping gene aad (lap) can be used for detection of either all species of Listeria sensu stricto or certain individual Listeria species in a mixture from food with a detection limit of about 10⁴ CFU/mL.
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Singh AK, Drolia R, Bai X, Bhunia AK. Streptomycin Induced Stress Response in Salmonella enterica Serovar Typhimurium Shows Distinct Colony Scatter Signature. PLoS One 2015; 10:e0135035. [PMID: 26252374 PMCID: PMC4529181 DOI: 10.1371/journal.pone.0135035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/16/2015] [Indexed: 11/18/2022] Open
Abstract
We investigated the streptomycin-induced stress response in Salmonella enterica serovars with a laser optical sensor, BARDOT (bacterial rapid detection using optical scattering technology). Initially, the top 20 S. enterica serovars were screened for their response to streptomycin at 100 μg/mL. All, but four S. enterica serovars were resistant to streptomycin. The MIC of streptomycin-sensitive serovars (Enteritidis, Muenchen, Mississippi, and Schwarzengrund) varied from 12.5 to 50 μg/mL, while streptomycin-resistant serovar (Typhimurium) from 125–250 μg/mL. Two streptomycin-sensitive serovars (Enteritidis and Mississippi) were grown on brain heart infusion (BHI) agar plates containing sub-inhibitory concentration of streptomycin (1.25–5 μg/mL) and a streptomycin-resistant serovar (Typhimurium) was grown on BHI containing 25–50 μg/mL of streptomycin and the colonies (1.2 ± 0.1 mm diameter) were scanned using BARDOT. Data show substantial qualitative and quantitative differences in the colony scatter patterns of Salmonella grown in the presence of streptomycin than the colonies grown in absence of antibiotic. Mass-spectrometry identified overexpression of chaperonin GroEL, which possibly contributed to the observed differences in the colony scatter patterns. Quantitative RT-PCR and immunoassay confirmed streptomycin-induced GroEL expression while, aminoglycoside adenylyltransferase (aadA), aminoglycoside efflux pump (aep), multidrug resistance subunit acrA, and ribosomal protein S12 (rpsL), involved in streptomycin resistance, were unaltered. The study highlights suitability of the BARDOT as a non-invasive, label-free tool for investigating stress response in Salmonella in conjunction with the molecular and immunoassay methods.
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Affiliation(s)
- Atul K. Singh
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Rishi Drolia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Xingjian Bai
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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Bhunia AK. One day to one hour: how quickly can foodborne pathogens be detected? Future Microbiol 2015; 9:935-46. [PMID: 25302952 DOI: 10.2217/fmb.14.61] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Foodborne pathogens pose serious public health risks. Rapid, accurate technologies to detect a low number of target cells (1 cell/25-325 g sample) and microbial toxins are in demand in order to assess product safety in hours to up to 1 day. Varied pathogen loads and the complexity of food present a major challenge. Current culture methods, while accurate, are lengthy. New methods, using brief culturing and detection kits (antibody based, nucleic acid amplification or nano/biosensors) or a culture-independent approach coupled with nucleic acid amplification, traditionally used for viruses/parasites, can be used to obtain results in hours. A strategic approach involving two-step, rapid, high-throughput screening to rule out negatives followed by a confirmatory test could accomplish product testing in 1 h to 1 day.
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He Y, Reed S, Bhunia AK, Gehring A, Nguyen LH, Irwin PL. Rapid identification and classification of Campylobacter spp. using laser optical scattering technology. Food Microbiol 2015; 47:28-35. [DOI: 10.1016/j.fm.2014.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 09/10/2014] [Accepted: 11/08/2014] [Indexed: 10/24/2022]
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Pan W, Zhao J, Chen Q. Classification of foodborne pathogens using near infrared (NIR) laser scatter imaging system with multivariate calibration. Sci Rep 2015; 5:9524. [PMID: 25860918 PMCID: PMC5381752 DOI: 10.1038/srep09524] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 03/09/2015] [Indexed: 11/21/2022] Open
Abstract
An optical sensor system, namely NIR laser scatter imaging system, was developed for rapid and noninvasive classification of foodborne pathogens. This developed system was used for images acquisition. The current study is focused on exploring the potential of this system combined with multivariate calibrations in classifying three categories of popular bacteria. Initially, normalization and Zernike moments extraction were performed, and the resultant translation, scale and rotation invariances were applied as the characteristic variables for subsequent discriminant analysis. Both linear (LDA, KNN and PLSDA) and nonlinear (BPANN, SVM and OSELM) pattern recognition methods were employed comparatively for modeling, and optimized by cross validation. Experimental results showed that the performances of nonlinear tools were superior to those of linear tools, especially for OSELM model with 95% discrimination rate in the prediction set. The overall results showed that it is extremely feasible for rapid and noninvasive classifying foodborne pathogens using this developed system combined with appropriate multivariate calibration.
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Affiliation(s)
- Wenxiu Pan
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Jiewen Zhao
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Quansheng Chen
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
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Kim H, Doh IJ, Bhunia AK, King GB, Bae E. Scalar diffraction modeling of multispectral forward scatter patterns from bacterial colonies. OPTICS EXPRESS 2015; 23:8545-8554. [PMID: 25968692 DOI: 10.1364/oe.23.008545] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A theoretical model for spectral forward scatter patterns from a bacterial colony based on elastic light scatter is presented. The spectral forward scatter patterns are computed by scalar diffraction theory, and compared with experimental results of three discrete wavelengths (405 nm, 635 nm, and 904 nm). To provide quantitative analysis, spectral dependence of diffraction ring width, gap, maxima, minima, and the first deflection point are monitored. Both model and experiment results show an excellent agreement; a longer wavelength induces a wider ring width, a wider ring gap, a smaller pattern size, and smaller numbers of rings. Further analysis using spatial fast Fourier transform (SFFT) shows a good agreement; the spatial frequencies are increasing towards the inward direction, and the slope is inversely proportional to the incoming wavelength.
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Singh AK, Sun X, Bai X, Kim H, Abdalhaseib MU, Bae E, Bhunia AK. Label-free, non-invasive light scattering sensor for rapid screening of Bacillus colonies. J Microbiol Methods 2015; 109:56-66. [DOI: 10.1016/j.mimet.2014.12.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 12/17/2014] [Accepted: 12/18/2014] [Indexed: 11/26/2022]
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Kim H, Singh AK, Bhunia AK, Bae E. Laser-induced speckle scatter patterns in Bacillus colonies. Front Microbiol 2014; 5:537. [PMID: 25352840 PMCID: PMC4196546 DOI: 10.3389/fmicb.2014.00537] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 09/26/2014] [Indexed: 11/20/2022] Open
Abstract
Label-free bacterial colony phenotyping technology called BARDOT (Bacterial Rapid Detection using Optical scattering Technology) provided successful classification of several different bacteria at the genus, species, and serovar level. Recent experiments with colonies of Bacillus species provided strikingly different characteristics of elastic light scatter (ELS) patterns, which were comprised of random speckles compared to other bacteria, which are dominated by concentric rings and spokes. Since this laser-based optical sensor interrogates the whole volume of the colony, 3-D information of micro- and macro-structures are all encoded in the far-field scatter patterns. Here, we present a theoretical model explaining the underlying mechanism of the speckle formation by the colonies from Bacillus species. Except for Bacillus polymyxa, all Bacillus spp. produced random bright spots on the imaging plane, which presumably dependent on the cellular and molecular organization and content within the colony. Our scatter model-based analysis revealed that colony spread resulting in variable surface roughness can modify the wavefront of the scatter field. As the center diameter of the Bacillus spp. colony grew from 500 to 900 μm, average speckles area decreased two-fold and the number of small speckles increased seven-fold. In conclusion, as Bacillus colony grows, the average speckle size in the scatter pattern decreases and the number of smaller speckle increases due to the swarming growth characteristics of bacteria within the colony.
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Affiliation(s)
- Huisung Kim
- Applied Optics Laboratory, School of Mechanical Engineering, Purdue University West Lafayette, IN, USA
| | - Atul K Singh
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University West Lafayette, IN, USA
| | - Arun K Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University West Lafayette, IN, USA
| | - Euiwon Bae
- Applied Optics Laboratory, School of Mechanical Engineering, Purdue University West Lafayette, IN, USA
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Tang Y, Kim H, Singh AK, Aroonnual A, Bae E, Rajwa B, Fratamico PM, Bhunia AK. Light scattering sensor for direct identification of colonies of Escherichia coli serogroups O26, O45, O103, O111, O121, O145 and O157. PLoS One 2014; 9:e105272. [PMID: 25136836 PMCID: PMC4138183 DOI: 10.1371/journal.pone.0105272] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 07/18/2014] [Indexed: 12/16/2022] Open
Abstract
Background Shiga-toxin producing Escherichia coli (STEC) have emerged as important foodborne pathogens, among which seven serogroups (O26, O45, O103, O111, O121, O145, O157) are most frequently implicated in human infection. The aim was to determine if a light scattering sensor can be used to rapidly identify the colonies of STEC serogroups on selective agar plates. Methodology/Principal Findings Initially, a total of 37 STEC strains representing seven serovars were grown on four different selective agar media, including sorbitol MacConkey (SMAC), Rainbow Agar O157, BBL CHROMagarO157, and R&F E. coli O157:H7, as well as nonselective Brain Heart Infusion agar. The colonies were scanned by an automated light scattering sensor, known as BARDOT (BActerial Rapid Detection using Optical scattering Technology), to acquire scatter patterns of STEC serogroups, and the scatter patterns were analyzed using an image classifier. Among all of the selective media tested, both SMAC and Rainbow provided the best differentiation results allowing multi-class classification of all serovars with an average accuracy of more than 90% after 10–12 h of growth, even though the colony appearance was indistinguishable at that early stage of growth. SMAC was chosen for exhaustive scatter image library development, and 36 additional strains of O157:H7 and 11 non-O157 serovars were examined, with each serogroup producing unique differential scatter patterns. Colony scatter images were also tested with samples derived from pure and mixed cultures, as well as experimentally inoculated food samples. BARDOT accurately detected O157 and O26 serovars from a mixed culture and also from inoculated lettuce and ground beef (10-h broth enrichment +12-h on-plate incubation) in the presence of natural background microbiota in less than 24 h. Conclusions BARDOT could potentially be used as a screening tool during isolation of the most important STEC serovars on selective agar plates from food samples in less than 24 h.
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Affiliation(s)
- Yanjie Tang
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Huisung Kim
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, United States of America
| | - Atul K. Singh
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Amornrat Aroonnual
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Euiwon Bae
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, United States of America
| | - Bartek Rajwa
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America
| | - Pina M. Fratamico
- USDA-ARS, Eastern Regional Research Center, Wyndmoor, Pennsylvania, United States of America
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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