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Williams A, Gaoh SD, Savenka A, Paredes A, Alusta P, Ahn Y, Buzatu DA. A flow cytometric assay to detect viability and persistence of Salmonella enterica subsp. enterica serotypes in nuclease-free water at 4 and 25°C. Front Microbiol 2024; 15:1342478. [PMID: 38435692 PMCID: PMC10906097 DOI: 10.3389/fmicb.2024.1342478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 02/05/2024] [Indexed: 03/05/2024] Open
Abstract
Salmonella spp. is one of the most isolated microorganisms reported to be responsible for human foodborne diseases and death. Water constitutes a major reservoir where the Salmonella spp. can persist and go undetected when present in low numbers. In this study, we assessed the viability of 12 serotypes of Salmonella enterica subsp. enterica for 160 days in nuclease-free water at 4 and 25°C using flow cytometry and Tryptic Soy Agar (TSA) plate counts. The results show that all 12 serotypes remain viable after 160 days in distilled water using flow cytometry, whereas traditional plate counts failed to detect ten serotypes incubated at 25°C. Moreover, the findings demonstrate that 4°C constitutes a more favorable environment where Salmonella can remain viable for prolonged periods without nutrients. Under such conditions, however, Salmonella exhibits a higher susceptibility to all tested antibiotics and benzalkonium chloride (BZK). The pre-enrichment with Universal Pre-enrichment Broth (UP) and 1/10 × Tryptic Soy broth (1/10 × TSB) resuscitated all tested serotypes on TSA plates, nevertheless cell size decreased after 160 days. Furthermore, phenotype microarray (PM) analysis of S. Inverness and S. Enteritidis combined with principal component analysis (PCA) revealed an inter-individual variability in serotypes with their phenotype characteristics, and the impact of long-term storage at 4 and 25°C for 160 days in nuclease-free water. This study provides an insight to Salmonella spp. long-term survivability at different temperatures and highlights the need for powerful tools to detect this microorganism to reduce the risk of disease transmission of foodborne pathogens via nuclease-free water.
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Affiliation(s)
- Anna Williams
- Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, United States
| | - Soumana Daddy Gaoh
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, United States
| | - Alena Savenka
- Office of Scientific Research, Nanotechnology Branch, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, United States
| | - Angel Paredes
- Office of Scientific Research, Nanotechnology Branch, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, United States
| | - Pierre Alusta
- Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, United States
| | - Youngbeom Ahn
- Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, United States
| | - Dan A. Buzatu
- Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, United States
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Zhuang L, Gong J, Zhao Y, Yang J, Liu G, Zhao B, Song C, Zhang Y, Shen Q. Progress in methods for the detection of viable Escherichia coli. Analyst 2024; 149:1022-1049. [PMID: 38273740 DOI: 10.1039/d3an01750h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Escherichia coli (E. coli) is a prevalent enteric bacterium and a necessary organism to monitor for food safety and environmental purposes. Developing efficient and specific methods is critical for detecting and monitoring viable E. coli due to its high prevalence. Conventional culture methods are often laborious and time-consuming, and they offer limited capability in detecting potentially harmful viable but non-culturable E. coli in the tested sample, which highlights the need for improved approaches. Hence, there is a growing demand for accurate and sensitive methods to determine the presence of viable E. coli. This paper scrutinizes various methods for detecting viable E. coli, including culture-based methods, molecular methods that target DNAs and RNAs, bacteriophage-based methods, biosensors, and other emerging technologies. The review serves as a guide for researchers seeking additional methodological options and aiding in the development of rapid and precise assays. Moving forward, it is anticipated that methods for detecting E. coli will become more stable and robust, ultimately contributing significantly to the improvement of food safety and public health.
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Affiliation(s)
- Linlin Zhuang
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
- State Key Laboratory of Digital Medical Engineering, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering & Basic Medicine Research and Innovation Center of Ministry of Education, Zhongda Hospital, Southeast University, Nanjing 211102, P. R. China.
| | - Jiansen Gong
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou 225125, P. R. China
| | - Ying Zhao
- State Key Laboratory of Digital Medical Engineering, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering & Basic Medicine Research and Innovation Center of Ministry of Education, Zhongda Hospital, Southeast University, Nanjing 211102, P. R. China.
| | - Jianbo Yang
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
| | - Guofang Liu
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
| | - Bin Zhao
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
| | - Chunlei Song
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
| | - Yu Zhang
- State Key Laboratory of Digital Medical Engineering, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering & Basic Medicine Research and Innovation Center of Ministry of Education, Zhongda Hospital, Southeast University, Nanjing 211102, P. R. China.
| | - Qiuping Shen
- School of Animal Husbandry and Veterinary Medicine, Jiangsu Vocational College of Agriculture and Forestry, Jurong 212400, P. R. China.
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Marcos-Fernández R, Sánchez B, Ruiz L, Margolles A. Convergence of flow cytometry and bacteriology. Current and future applications: a focus on food and clinical microbiology. Crit Rev Microbiol 2023; 49:556-577. [PMID: 35749433 DOI: 10.1080/1040841x.2022.2086035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 05/12/2022] [Accepted: 05/31/2022] [Indexed: 11/03/2022]
Abstract
Since its development in the 1960s, flow cytometry (FCM) was quickly revealed a powerful tool to analyse cell populations in medical studies, yet, for many years, was almost exclusively used to analyse eukaryotic cells. Instrument and methodological limitations to distinguish genuine bacterial signals from the background, among other limitations, have hampered FCM applications in bacteriology. In recent years, thanks to the continuous development of FCM instruments and methods with a higher discriminatory capacity to detect low-size particles, FCM has emerged as an appealing technique to advance the study of microbes, with important applications in research, clinical and industrial settings. The capacity to rapidly enumerate and classify individual bacterial cells based on viability facilitates the monitoring of bacterial presence in foodstuffs or clinical samples, reducing the time needed to detect contamination or infectious processes. Besides, FCM has stood out as a valuable tool to advance the study of complex microbial communities, or microbiomes, that are very relevant in the context of human health, as well as to understand the interaction of bacterial and host cells. This review highlights current developments in, and future applications of, FCM in bacteriology, with a focus on those related to food and clinical microbiology.
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Affiliation(s)
- Raquel Marcos-Fernández
- Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Asturias, Spain
| | - Borja Sánchez
- Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Asturias, Spain
| | - Lorena Ruiz
- Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Asturias, Spain
| | - Abelardo Margolles
- Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Asturias, Spain
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Specific Detection and Enumeration of Burkholderia cepacia Complex by Flow Cytometry Using a Fluorescence-Labeled Oligonucleotide Probe. Microorganisms 2022; 10:microorganisms10061170. [PMID: 35744688 PMCID: PMC9227203 DOI: 10.3390/microorganisms10061170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 05/29/2022] [Accepted: 05/30/2022] [Indexed: 11/16/2022] Open
Abstract
Burkholderia cepacia complex (BCC) contamination has resulted in recalls of non-sterile pharmaceutical products. The fast, sensitive, and specific detection of BCC is critical for ensuring the quality and safety of pharmaceutical products. In this study, a rapid flow cytometry-based detection method was developed using a fluorescence-labeled oligonucleotide Kef probe that specifically binds a KefB/KefC membrane protein sequence within BCC. Optimal conditions of a 1 nM Kef probe concentration at a 60 °C hybridization temperature for 30 min were determined and applied for the flow cytometry assay. The true-positive rate (sensitivity) and true-negative rate (specificity) of the Kef probe assay were 90% (18 positive out of 20 BCC species) and 88.9% (16 negative out of 18 non-BCC), respectively. The detection limit for B. cenocepacia AU1054 with the Kef probe flow cytometry assay in nuclease-free water was 1 CFU/mL. The average cell counts using the Kef probe assay from a concentration of 10 μg/mL chlorhexidine gluconate and 50 μg/mL benzalkonium chloride were similar to those of the RAPID-B total plate count (TPC). We demonstrate the potential of Kef probe flow cytometry as a more sensitive alternative to culture-based methods for detecting BCC in non-sterilized pharmaceutical raw materials and products with regards to water-based environments.
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A comparison of culture-based, real-time PCR, droplet digital PCR and flow cytometric methods for the detection of Burkholderia cepacia complex in nuclease-free water and antiseptics. J Ind Microbiol Biotechnol 2020; 47:475-484. [PMID: 32671501 DOI: 10.1007/s10295-020-02287-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/17/2020] [Indexed: 12/14/2022]
Abstract
The presence of Burkholderia cepacia complex (BCC) strains has resulted in recalls of pharmaceutical products, since these opportunistic pathogens can cause serious infections. Rapid and sensitive diagnostic methods to detect BCC are crucial to determine contamination levels. We evaluated bacterial cultures, real-time PCR (qPCR), droplet digital PCR (ddPCR), and flow cytometry to detect BCC in nuclease-free water, in chlorhexidine gluconate (CHX) and benzalkonium chloride (BZK) solutions. Twenty BCC strains were each suspended (1, 10, 100, and 1000 CFU/ml) in autoclaved nuclease-free water, 10 μg/ml CHX, and 50 μg/ml BZK. Five replicates of each strain were tested at each concentration (20 strains × 4 concentrations × 5 replicates = 400 tests) to detect BCC using the aforementioned four methods. We demonstrated the potential of ddPCR and flow cytometry as more sensitive alternatives to culture-based methods to detect BCC in autoclaved nuclease-free water and antiseptics samples.
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Liu S, Sui Z, Lin J, Huo N, Yang J, Wang B, Gu S. Rapid detection of single viableEscherichia coliO157:H7 cells in milk by flow cytometry. J Food Saf 2019. [DOI: 10.1111/jfs.12657] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Siyuan Liu
- Shanxi Key Laboratory of Environmental Veterinary Medicine, College of Animal Science and Veterinary MedicineShanxi Agricultural University Taigu Shanxi China
- Center for Advanced Measurement ScienceNational Institute of Metrology Beijing China
| | - Zhiwei Sui
- Center for Advanced Measurement ScienceNational Institute of Metrology Beijing China
| | - Jing Lin
- Department of BiometrologyInstitute of Measurement and Testing Technology Nanjing Jiangsu China
| | - Nairui Huo
- Shanxi Key Laboratory of Environmental Veterinary Medicine, College of Animal Science and Veterinary MedicineShanxi Agricultural University Taigu Shanxi China
| | - Jiayi Yang
- Center for Advanced Measurement ScienceNational Institute of Metrology Beijing China
| | - Bin Wang
- Center for Advanced Measurement ScienceNational Institute of Metrology Beijing China
- Research Center for Ginseng Genetic Resources Development and UtilizationJilin Agricultural University Jilin China
| | - Shaopeng Gu
- Shanxi Key Laboratory of Environmental Veterinary Medicine, College of Animal Science and Veterinary MedicineShanxi Agricultural University Taigu Shanxi China
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Wilkinson MG. Flow cytometry as a potential method of measuring bacterial viability in probiotic products: A review. Trends Food Sci Technol 2018. [DOI: 10.1016/j.tifs.2018.05.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Williams AJ, Cooper WM, Ramsaroop S, Alusta P, Buzatu DA, Wilkes JG. Rapid Flow Cytometry Detection of a Single Viable Escherichia coli O157:H7 Cell in Raw Spinach Using a Simplified Sample Preparation Technique. Front Microbiol 2017; 8:1493. [PMID: 28855894 PMCID: PMC5558463 DOI: 10.3389/fmicb.2017.01493] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/25/2017] [Indexed: 11/13/2022] Open
Abstract
Very low cell count detection of Escherichia coli O157:H7 in foods is critical, since an infective dose for this pathogen may be only 10 cells, and fewer still for vulnerable populations. A flow cytometer is able to detect and count individual cells of a target bacterium, in this case E. coli O157:H7. The challenge is to find the single cell in a complex matrix like raw spinach. To find that cell requires growing it as quickly as possible to a number sufficiently in excess of matrix background that identification is certain. The experimental design for this work was that of a U.S. Food and Drug Administration (FDA) In-House Level 3 validation executed in the technology’s originating laboratory. Using non-selective enrichment broth, 6.5 h incubation at 42°C, centrifugation for target cell concentration, and a highly selective E. coli O157 fluorescent antibody tag, the cytometry method proved more sensitive than a reference regulatory method (p = 0.01) for detecting a single target cell, one E. coli O157:H7 cell, in 25 g of spinach. It counted that cell’s daughters with at least 38× signal-to-noise ratio, analyzing 25 samples in total-time-to-results of 9 h.
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Affiliation(s)
- Anna J Williams
- Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, JeffersonAR, United States
| | - Willie M Cooper
- Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, JeffersonAR, United States
| | | | - Pierre Alusta
- Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, JeffersonAR, United States
| | - Dan A Buzatu
- Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, JeffersonAR, United States
| | - Jon G Wilkes
- Division of Systems Biology, National Center for Toxicological Research, U.S. Food and Drug Administration, JeffersonAR, United States
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