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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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Bäuerl C, Randazzo W, Sánchez G, Selma-Royo M, García Verdevio E, Martínez L, Parra-Llorca A, Lerin C, Fumadó V, Crovetto F, Crispi F, Pérez-Cano FJ, Rodríguez G, Ruiz-Redondo G, Campoy C, Martínez-Costa C, Collado MC. SARS-CoV-2 RNA and antibody detection in breast milk from a prospective multicentre study in Spain. Arch Dis Child Fetal Neonatal Ed 2022; 107:216-221. [PMID: 34417223 DOI: 10.1101/2021.05.06.21256766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 07/12/2021] [Indexed: 05/21/2023]
Abstract
OBJECTIVES To develop and validate a specific protocol for SARS-CoV-2 detection in breast milk matrix and to determine the impact of maternal SARS-CoV-2 infection on the presence, concentration and persistence of specific SARS-CoV-2 antibodies. DESIGN AND PATIENTS This is a prospective, multicentre longitudinal study (April-December 2020) in 60 mothers with SARS-CoV-2 infection and/or who have recovered from COVID-19. A control group of 13 women before the pandemic were also included. SETTING Seven health centres from different provinces in Spain. MAIN OUTCOME MEASURES Presence of SARS-CoV-2 RNA in breast milk, targeting the N1 region of the nucleocapsid gene and the envelope (E) gene; presence and levels of SARS-CoV-2-specific immunoglobulins (Igs)-IgA, IgG and IgM-in breast milk samples from patients with COVID-19. RESULTS All breast milk samples showed negative results for presence of SARS-CoV-2 RNA. We observed high intraindividual and interindividual variability in the antibody response to the receptor-binding domain of the SARS-CoV-2 spike protein for each of the three isotypes IgA, IgM and IgG. Main Protease (MPro) domain antibodies were also detected in milk. 82.9% (58 of 70) of milk samples were positive for at least one of the three antibody isotypes, with 52.9% of these positive for all three Igs. Positivity rate for IgA was relatively stable over time (65.2%-87.5%), whereas it raised continuously for IgG (from 47.8% for the first 10 days to 87.5% from day 41 up to day 206 post-PCR confirmation). CONCLUSIONS Our study confirms the safety of breast feeding and highlights the relevance of virus-specific SARS-CoV-2 antibody transfer. This study provides crucial data to support official breastfeeding recommendations based on scientific evidence. Trial registration number NCT04768244.
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Affiliation(s)
- Christine Bäuerl
- Department of Biotechnology, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
| | - Walter Randazzo
- Department of Preservation and Food Safety Technologies, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
| | - Gloria Sánchez
- Department of Preservation and Food Safety Technologies, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
| | - Marta Selma-Royo
- Department of Biotechnology, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
| | - Elia García Verdevio
- Department of Gynecology and Obstetrics, Hospital Universitario Dr Peset, Valencia, Spain
| | - Laura Martínez
- Department of Paediatrics, Hospital Clínico Universitario de Valencia, Nutrition Research Group of INCLIVA, Valencia, Spain
| | - Anna Parra-Llorca
- Health Research Institute La Fe, Neonatal Research Group and University and Polytechnic Hospital La Fe, Division of Neonatology, Valencia, Spain
| | - Carles Lerin
- Department of Endocrinology, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Victoria Fumadó
- Department of Infectious and Imported Diseases, Paediatric Unit, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Francesca Crovetto
- BCNatal - Barcelona Center for Maternal-Fetal and Neonatal Medicine, Hospital Sant Joan de Déu and Hospital Clínic, University of Barcelona, CIBERER, Barcelona, Spain
| | - Fatima Crispi
- BCNatal - Barcelona Center for Maternal-Fetal and Neonatal Medicine, Hospital Sant Joan de Déu and Hospital Clínic, University of Barcelona, CIBERER, Barcelona, Spain
| | - Francisco J Pérez-Cano
- Department of Biochemistry and Physiology, Faculty of Pharmacy and Food Science, University of Barcelona, Barcelona, Spain
| | - Gerardo Rodríguez
- University of Zaragoza, Hospital Clínico Universitario Lozano Blesa, Zaragoza. Instituto de Investigación Sanitaria Aragón (IIS Aragón), Red de Salud Materno Infantil y del Desarrollo (SAMID), Zaragoza, Spain
| | - Gemma Ruiz-Redondo
- Department of Gynecology and Obstetrics, University Hospital Clinic "San Cecilio" - Health Sciences Technological Park (PTS), Granada, Spain
| | - Cristina Campoy
- Department of Paediatrics, University of Granada, Granada, Spain
| | - Cecilia Martínez-Costa
- Department of Paediatrics, Hospital Clínico Universitario de Valencia, Nutrition Research Group of INCLIVA, Valencia, Spain
| | - Maria Carmen Collado
- Department of Biotechnology, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
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3
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Bäuerl C, Randazzo W, Sánchez G, Selma-Royo M, García Verdevio E, Martínez L, Parra-Llorca A, Lerin C, Fumadó V, Crovetto F, Crispi F, Pérez-Cano FJ, Rodríguez G, Ruiz-Redondo G, Campoy C, Martínez-Costa C, Collado MC. SARS-CoV-2 RNA and antibody detection in breast milk from a prospective multicentre study in Spain. Arch Dis Child Fetal Neonatal Ed 2022; 107:216-221. [PMID: 34417223 PMCID: PMC8384494 DOI: 10.1136/archdischild-2021-322463] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 07/12/2021] [Indexed: 01/09/2023]
Abstract
OBJECTIVES To develop and validate a specific protocol for SARS-CoV-2 detection in breast milk matrix and to determine the impact of maternal SARS-CoV-2 infection on the presence, concentration and persistence of specific SARS-CoV-2 antibodies. DESIGN AND PATIENTS This is a prospective, multicentre longitudinal study (April-December 2020) in 60 mothers with SARS-CoV-2 infection and/or who have recovered from COVID-19. A control group of 13 women before the pandemic were also included. SETTING Seven health centres from different provinces in Spain. MAIN OUTCOME MEASURES Presence of SARS-CoV-2 RNA in breast milk, targeting the N1 region of the nucleocapsid gene and the envelope (E) gene; presence and levels of SARS-CoV-2-specific immunoglobulins (Igs)-IgA, IgG and IgM-in breast milk samples from patients with COVID-19. RESULTS All breast milk samples showed negative results for presence of SARS-CoV-2 RNA. We observed high intraindividual and interindividual variability in the antibody response to the receptor-binding domain of the SARS-CoV-2 spike protein for each of the three isotypes IgA, IgM and IgG. Main Protease (MPro) domain antibodies were also detected in milk. 82.9% (58 of 70) of milk samples were positive for at least one of the three antibody isotypes, with 52.9% of these positive for all three Igs. Positivity rate for IgA was relatively stable over time (65.2%-87.5%), whereas it raised continuously for IgG (from 47.8% for the first 10 days to 87.5% from day 41 up to day 206 post-PCR confirmation). CONCLUSIONS Our study confirms the safety of breast feeding and highlights the relevance of virus-specific SARS-CoV-2 antibody transfer. This study provides crucial data to support official breastfeeding recommendations based on scientific evidence. Trial registration number NCT04768244.
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Affiliation(s)
- Christine Bäuerl
- Department of Biotechnology, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
| | - Walter Randazzo
- Department of Preservation and Food Safety Technologies, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
| | - Gloria Sánchez
- Department of Preservation and Food Safety Technologies, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
| | - Marta Selma-Royo
- Department of Biotechnology, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
| | - Elia García Verdevio
- Department of Gynecology and Obstetrics, Hospital Universitario Dr Peset, Valencia, Spain
| | - Laura Martínez
- Department of Paediatrics, Hospital Clínico Universitario de Valencia, Nutrition Research Group of INCLIVA, Valencia, Spain
| | - Anna Parra-Llorca
- Health Research Institute La Fe, Neonatal Research Group and University and Polytechnic Hospital La Fe, Division of Neonatology, Valencia, Spain
| | - Carles Lerin
- Department of Endocrinology, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Victoria Fumadó
- Department of Infectious and Imported Diseases, Paediatric Unit, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Francesca Crovetto
- BCNatal - Barcelona Center for Maternal-Fetal and Neonatal Medicine, Hospital Sant Joan de Déu and Hospital Clínic, University of Barcelona, CIBERER, Barcelona, Spain
| | - Fatima Crispi
- BCNatal - Barcelona Center for Maternal-Fetal and Neonatal Medicine, Hospital Sant Joan de Déu and Hospital Clínic, University of Barcelona, CIBERER, Barcelona, Spain
| | - Francisco J Pérez-Cano
- Department of Biochemistry and Physiology, Faculty of Pharmacy and Food Science, University of Barcelona, Barcelona, Spain
| | - Gerardo Rodríguez
- University of Zaragoza, Hospital Clínico Universitario Lozano Blesa, Zaragoza. Instituto de Investigación Sanitaria Aragón (IIS Aragón), Red de Salud Materno Infantil y del Desarrollo (SAMID), Zaragoza, Spain
| | - Gemma Ruiz-Redondo
- Department of Gynecology and Obstetrics, University Hospital Clinic “San Cecilio” – Health Sciences Technological Park (PTS), Granada, Spain
| | - Cristina Campoy
- Department of Paediatrics, University of Granada, Granada, Spain
| | - Cecilia Martínez-Costa
- Department of Paediatrics, Hospital Clínico Universitario de Valencia, Nutrition Research Group of INCLIVA, Valencia, Spain
| | - Maria Carmen Collado
- Department of Biotechnology, Institute of Agrochemistry and Food Technology-National Research Council (IATA-CSIC), Paterna, Valencia, Spain
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Güner D, Şener BB, Bayraç C. Label free detection of auramine O by G-quadruplex-based fluorescent turn-on strategy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 267:120532. [PMID: 34776374 DOI: 10.1016/j.saa.2021.120532] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
Auramine o (AO) is a synthetic dye used in paper and textile industries. Although it has been an unauthorized food additive in many countries due to its toxic and carcinogenic possibility, its illegal uses have been detected in certain food products such as pasta, semolina and spices and also in pharmaceuticals. The presence of AO in food products should be monitored, therefore, to minimize the negative health effects on consumers. In this study, a simple, highly sensitive and selective label free detection method was investigated for AO by G-quadruplex-based fluorescent turn-on strategy. The optimum fluorescent detection assay was achieved with a specific G-quadruplex DNA sequence, c-myc, at 400 nM in Tris-HCl buffer at pH 7.4. The linearity of fluorescence intensity depending on AO concentration ranged from 0 to 0.07 µM and LOD and LOQ were 3 nM and 10 nM, respectively. The G-quadruplex-based detection assay was highly specific for AO as compared to other two synthetic food colorings and successfully applied to determine AO in pasta, bulgur and curry powder with recoveries in the range from 70.33% to 106.49%. This G-quadruplex-based label free detection assay has a significant potential to be used in the detection of AO in food products.
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Affiliation(s)
- Dilan Güner
- Department of Bioengineering, Karamanoğlu Mehmetbey University, Karaman, Turkey
| | | | - Ceren Bayraç
- Department of Bioengineering, Karamanoğlu Mehmetbey University, Karaman, Turkey.
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5
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Antimicrobial Resistance Gene Detection Methods for Bacteria in Animal-Based Foods: A Brief Review of Highlights and Advantages. Microorganisms 2021; 9:microorganisms9050923. [PMID: 33925810 PMCID: PMC8146338 DOI: 10.3390/microorganisms9050923] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 01/06/2023] Open
Abstract
Antimicrobial resistance is a major public health problem and is mainly due to the indiscriminate use of antimicrobials in human and veterinary medicine. The consumption of animal-based foods can contribute to the transfer of these genes between animal and human bacteria. Resistant and multi-resistant bacteria such as Salmonella spp. and Campylobacter spp. have been detected both in animal-based foods and in production environments such as farms, industries and slaughterhouses. This review aims to compile the techniques for detecting antimicrobial resistance using traditional and molecular methods, highlighting their advantages and disadvantages as well as the effectiveness and confidence of their results.
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6
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Bahlinger E, Dorn-In S, Beindorf PM, Mang S, Kaltner F, Gottschalk C, Gareis M, Schwaiger K. Development of two specific multiplex qPCRs to determine amounts of Pseudomonas, Enterobacteriaceae, Brochothrix thermosphacta and Staphylococcus in meat and heat-treated meat products. Int J Food Microbiol 2020; 337:108932. [PMID: 33152570 DOI: 10.1016/j.ijfoodmicro.2020.108932] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/20/2020] [Accepted: 10/15/2020] [Indexed: 10/23/2022]
Abstract
Culturing methods are conventionally applied to investigate the contamination of food with several microorganisms after heat processing. However, with these methods, it is not possible to evaluate whether heat-treated meat products, such as cooked sausages, contained parts of spoiled meat. Therefore, two specific multiplex qPCRs were developed in this study in order to determine the microbiological quality of the raw materials used for these products. The PCR targets focused on four bacterial groups often found on meat (family Enterobacteriaceae, genus Pseudomonas, genus Staphylococcus and species Brochothrix thermosphacta). Specificity as well as sensitivity of the developed multiplex qPCRs, validated by using 68 microbial species, were 100%. The applicability of both multiplex qPCRs compared to culturing methods was performed using 96 meat samples (fresh and naturally spoiled) and 12 inhouse-made "Lyoner" sausages containing variable ratios of spoiled meat (0%, 5%, 12% and 25%; n = 3 for each group). Both methods showed similar results by evaluating the ∆log10 cfu/g, the relative accuracy and the t-test analysis (p > 0.05). Comparing qPCR results of the different sausage groups, a significant difference between sausages containing fresh meat and sausages containing spoiled meat (12% and 25%) was found only for Pseudomonas and B. thermosphacta in both raw and cooked sausages. The statistical difference between 5% vs. 12% and 25% spoiled meat in cooked sausages, was also found only for these two bacterial groups. The developed multiplex qPCRs were further applied to 30 commercially available "Bologna-type" sausages. The results showed a total of 14 sausages considered to be suspicious for Food Fraud. While the role of Staphylococcus spp. in meat spoilage remains unclear, Pseudomonas, Enterobacteriaceae and B. thermosphacta could together be used as an indicator for "spoiled meat" used in sausages. The developed qPCR systems in this study allow the detection of four relevant bacterial groups in the heated Bologna-type sausages and provide information about the hygienic quality of raw materials used. This method could thus be helpful for screening food suspected of Food Fraud.
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Affiliation(s)
- Eunike Bahlinger
- Faculty of Veterinary Medicine, Chair of Food Safety, LMU Munich, Schoenleutnerstr. 8, 85716 Oberschleissheim, Germany.
| | - Samart Dorn-In
- Faculty of Veterinary Medicine, Chair of Food Safety, LMU Munich, Schoenleutnerstr. 8, 85716 Oberschleissheim, Germany
| | - Philipp-Michael Beindorf
- Faculty of Veterinary Medicine, Chair of Food Safety, LMU Munich, Schoenleutnerstr. 8, 85716 Oberschleissheim, Germany
| | - Sirkka Mang
- Faculty of Veterinary Medicine, Chair of Food Safety, LMU Munich, Schoenleutnerstr. 8, 85716 Oberschleissheim, Germany
| | - Florian Kaltner
- Faculty of Veterinary Medicine, Chair of Food Safety, LMU Munich, Schoenleutnerstr. 8, 85716 Oberschleissheim, Germany
| | - Christoph Gottschalk
- Faculty of Veterinary Medicine, Chair of Food Safety, LMU Munich, Schoenleutnerstr. 8, 85716 Oberschleissheim, Germany
| | - Manfred Gareis
- Faculty of Veterinary Medicine, Chair of Food Safety, LMU Munich, Schoenleutnerstr. 8, 85716 Oberschleissheim, Germany
| | - Karin Schwaiger
- Faculty of Veterinary Medicine, Chair of Food Safety, LMU Munich, Schoenleutnerstr. 8, 85716 Oberschleissheim, Germany
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7
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Yin H, Lin Y, Lin C, Tsai W, Wen H. Rapid and sensitive detection ofStaphylococcus aureusin processed foods using a field‐deployed device to perform an insulated isothermal polymerase chain reaction‐based assay. J Food Saf 2019. [DOI: 10.1111/jfs.12690] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hsin‐Yi Yin
- Department of Food Science and BiotechnologyNational Chung Hsing University Taichung Taiwan, ROC
| | - Yu‐Yi Lin
- Department of Food Science and BiotechnologyNational Chung Hsing University Taichung Taiwan, ROC
| | | | - Wen‐Che Tsai
- Department of Food Science and BiotechnologyNational Chung Hsing University Taichung Taiwan, ROC
| | - Hsiao‐Wei Wen
- Department of Food Science and BiotechnologyNational Chung Hsing University Taichung Taiwan, ROC
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8
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Wang Y, Salazar JK. Culture-Independent Rapid Detection Methods for Bacterial Pathogens and Toxins in Food Matrices. Compr Rev Food Sci Food Saf 2015; 15:183-205. [DOI: 10.1111/1541-4337.12175] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 09/14/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Yun Wang
- Div. of Food Processing Science and Technology; U.S. Food and Drug Administration; Bedford Park IL U.S.A
| | - Joelle K. Salazar
- Div. of Food Processing Science and Technology; U.S. Food and Drug Administration; Bedford Park IL U.S.A
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9
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MURAKAMI TAKU. Filter-Based Pathogen Enrichment Technology for Detection of Multiple Viable Foodborne Pathogens in 1 Day. J Food Prot 2012; 75:1603-10. [DOI: 10.4315/0362-028x.jfp-12-039] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Conventional foodborne pathogen assays currently used in the food industry often require long culture enrichments to increase pathogen levels so they can be detected. Even using sensitive real-time PCR assays, culture enrichment at least overnight is necessary especially for detection of pathogens with slow growth rates such as Listeria monocytogenes. To eliminate this cumbersome enrichment step and detect minute amounts of pathogens within 1 day, filter-based pathogen enrichment technology was developed utilizing a unique combination of glass fiber depth filter and porous filter aid materials to efficiently separate pathogens from food homogenates and avoid filter clogging by food particles. After pathogen immobilization in depth filters, only viable pathogens were selectively collected in a small volume of growth medium via microbial multiplication and migration; nonviable pathogens remained inside the filters. By assaying viable pathogens using real-time PCRs, multiple species of foodborne pathogens were detected, including L. monocytogenes, Salmonella enterica, and Escherichia coli O157:H7, at around 1 CFU/ml or 1 CFU/g in various food samples. This filter-based pathogen enrichment technology is a unique bacterial enrichment alternative to the conventional culture enrichment step and can significantly shorten the time necessary to obtain assay results.
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Affiliation(s)
- TAKU MURAKAMI
- Hitachi Chemical Research Center, Inc., 1003 Health Sciences Road, Irvine, California 92617, USA
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10
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Wilkes JG, Tucker RK, Montgomery JA, Cooper WM, Sutherland JB, Buzatu DA. Reduction of food matrix interference by a combination of sample preparation and multi-dimensional gating techniques to facilitate rapid, high sensitivity analysis for Escherichia coli serotype O157 by flow cytometry. Food Microbiol 2012; 30:281-8. [DOI: 10.1016/j.fm.2011.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 11/03/2011] [Accepted: 11/06/2011] [Indexed: 11/30/2022]
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11
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Guarddon M, Miranda J, Rodríguez J, Vázquez B, Cepeda A, Franco C. Real-time polymerase chain reaction for the quantitative detection of tetA and tetB bacterial tetracycline resistance genes in food. Int J Food Microbiol 2011; 146:284-9. [DOI: 10.1016/j.ijfoodmicro.2011.02.026] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/21/2011] [Accepted: 02/21/2011] [Indexed: 10/18/2022]
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12
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Pennacchia C, Ercolini D, Villani F. Development of a Real-Time PCR assay for the specific detection of Brochothrix thermosphacta in fresh and spoiled raw meat. Int J Food Microbiol 2009; 134:230-6. [DOI: 10.1016/j.ijfoodmicro.2009.07.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 07/01/2009] [Accepted: 07/04/2009] [Indexed: 11/16/2022]
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13
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GRACIAS KIEVS, MCKILLIP JOHNL. NUCLEIC ACID SEQUENCE-BASED AMPLIFICATION (NASBA) IN MOLECULAR BACTERIOLOGY: A PROCEDURAL GUIDE. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1745-4581.2007.00099.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Bang W, Drake MA, Jaykus LA. Recovery and detection of Vibrio vulnificus during cold storage. Food Microbiol 2006; 24:664-70. [PMID: 17418319 DOI: 10.1016/j.fm.2006.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2006] [Revised: 11/17/2006] [Accepted: 12/12/2006] [Indexed: 11/16/2022]
Abstract
Different cultural techniques and molecular methods for the detection of Vibrio vulnificus during cold storage in a model broth system were compared. Two strains of V. vulnificus were grown to stationary phase and inoculated (10(6) CFU/mL) into tryptic soy broth with 2% sodium chloride (TSBN2) or artificial seawater (ASW), both pre-chilled to 5 degrees C. These were stored for 10 days, with sub-sampling conducted at time 0 and every 2 days thereafter. Each subsample was plated, by both pour and spread plate techniques, onto tryptic soy agar 2% sodium chloride (TSAN2) with or without catalase (400 or 600 U) or sodium pyruvate (80 or 160 mg) supplementation. Nucleic acids were extracted from subsamples and subjected to PCR and RT-PCR with hemolysin as the target. Higher recoveries of V. vulnificus were obtained with spread plating compared to pour plating (P<0.05). The addition of sodium pyruvate (80 mg) or catalase (400 U) significantly increased cell recovery (P<0.05). PCR amplification signals were stronger than RT-PCR signals at each timepoint, and results were generally consistent between TSAN2 and ASW for each strain. These results will aid in the design of optimum methods to recover and/or detect V. vulnificus cells subjected to sublethal stress that might be encountered in food processing and storage.
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Affiliation(s)
- W Bang
- Department of Food Science, North Carolina State University, Raleigh, NC 27695, USA
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15
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Cooper RM, McKillip JL. EnterotoxigenicBacillus spp. DNA fingerprint revealed in naturally contaminated nonfat dry milk powder using rep-PCR. J Basic Microbiol 2006; 46:358-64. [PMID: 17009291 DOI: 10.1002/jobm.200510132] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Dry milk powders and functional ingredients frequently contain high levels of viable bacterial spores, some of which may result in growth of toxigenic Bacillus spp. in reconstituted and temperature-abused foods. Samples from nonfat dry milk (NFDM), infant milk formula (IMF), coffee creamer, lecithin, and cocoa powder were subjected to a short heat treatment followed by enrichment in tryptone phosphate glucose yeast extract (TPGY) broth at 32 degrees C for 12-25 hours to obtain cell densities of 10(6) CFU ml(-1). DNA was extracted using a modification of established protocol, leading to the development of an optimized method for each food system. Purified DNA was amplified by rep-PCR using extragenic sequence-targeting primers and optimized for each food. PCR fingerprints from each food were analyzed electrophoretically for banding patterns earlier correlated to that of enterotoxigenic Bacillus spp. and Bacillus cereus positive control DNA fingerprints. Reverse passive latex agglutination (RPLA) and Bacillus Diarrhoeal Enterotoxin Enzyme Linked Immunosorbent Assay (Tecra Diagnostics) confirmed the presence of HBL and NHE enterotoxin production in NFDM, Coffee creamer, infant milk formula, and two lecithin samples but not in cocoa powder. These results demonstrate the utility of rep-PCR not only as a tool for bacterial genotyping, but a unique means of quality control and hygiene monitoring in food microbiology.
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Affiliation(s)
- Robin M Cooper
- Roche Diagnostics Corporation, Indianapolis, IN 46256, USA
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16
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Isonhood J, Drake M, Jaykus LA. Upstream sample processing facilitates PCR detection of Listeria monocytogenes in mayonnaise-based ready-to-eat (RTE) salads. Food Microbiol 2006; 23:584-90. [PMID: 16943055 DOI: 10.1016/j.fm.2005.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 09/26/2005] [Accepted: 09/26/2005] [Indexed: 01/24/2023]
Abstract
Sample pretreatment to reduce volume and concentrate cells of the target organism(s) prior to molecular detection offers a useful supplement or alternative to cultural enrichment. The purpose of this study was to develop an upstream processing method to facilitate the detection of Listeria monocytogenes in ready-to-eat (RTE) salads by PCR. Potato salad, a model RTE commodity, was seeded with L. monocytogenes and processed by two alternative upstream sample processing methods (designated one-step and two-step centrifugation), followed by DNA extraction, PCR amplification, and Southern hybridization. The two-step method resulted in 1,000-fold improvements in the PCR detection limit, from 10(6) Cfu/g (no sample processing) to 10(3) Cfu/g. The two-step method was applied for upstream sample processing of four representative deli salad items artificially inoculated with L. monocytogenes at levels ranging from 10(1)-10(6) Cfu/g. Following DNA extraction, PCR amplification, and Southern hybridization, detection was achieved at input levels of 10(5) Cfu/g for chicken salad, 10(4) Cfu/g for macaroni salad, and 10(3) Cfu/g for potato and seafood salads. The two-step method reported here facilitates the production of a final sample concentrate of reduced volume and improved purity which was compatible with PCR amplification. This approach offers further progress in our efforts to reduce or eliminate cultural enrichment in an effort to speed time to results when applying molecular methods to the detection of pathogens in foods.
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Affiliation(s)
- Jamie Isonhood
- Department of Food Science, North Carolina State University, Raleigh, North Carolina, USA
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17
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Martín B, Jofré A, Garriga M, Pla M, Aymerich T. Rapid quantitative detection of Lactobacillus sakei in meat and fermented sausages by real-time PCR. Appl Environ Microbiol 2006; 72:6040-8. [PMID: 16957227 PMCID: PMC1563650 DOI: 10.1128/aem.02852-05] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Accepted: 06/20/2006] [Indexed: 11/20/2022] Open
Abstract
A quick and simple method for quantitative detection of Lactobacillus sakei in fermented sausages was successfully developed. It is based on Chelex-100-based DNA purification and real-time PCR enumeration using a TaqMan fluorescence probe. Primers and probes were designed in the L. sakei 16S-23S rRNA intergenic transcribed spacer region, and the assay was evaluated using L. sakei genomic DNA and an artificially inoculated sausage model. The detection limit of this technique was approximately 3 cells per reaction mixture using both purified DNA and the inoculated sausage model. The quantification limit was established at 30 cells per reaction mixture in both models. The assay was then applied to enumerate L. sakei in real samples, and the results were compared to the MRS agar count method followed by confirmation of the percentage of L. sakei colonies. The results obtained by real-time PCR were not statistically significantly different than those obtained by plate count on MRS agar (P > 0.05), showing a satisfactory agreement between both methods. Therefore, the real-time PCR assay developed can be considered a promising rapid alternative method for the quantification of L. sakei and evaluation of the implantation of starter strains of L. sakei in fermented sausages.
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Affiliation(s)
- Belén Martín
- Institute for Food and Agricultural Research and Technology (IRTA), Meat Technology Center, Granja Camps i Armet, E-17121 Monells, Spain
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Johnston LM, Elhanafi D, Drake M, Jaykus LA. A simple method for the direct detection of Salmonella and Escherichia coli O157:H7 from raw alfalfa sprouts and spent irrigation water using PCR. J Food Prot 2005; 68:2256-63. [PMID: 16300060 DOI: 10.4315/0362-028x-68.11.2256] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The U.S. Food and Drug Administration recognizes that raw seed sprouts are an important cause of foodborne disease and is now recommending that either spent irrigation water or final product be screened for Salmonella and Escherichia coli O157:H7 as a means of assuring the safety of product intended for consumption. In an effort to streamline such testing efforts, a simple method to preconcentrate pathogens from sprouts and spent irrigation water was investigated to facilitate the direct (without prior cultural enrichment) detection of pathogens using the PCR technique. Alfalfa sprouts and spent irrigation water were seeded with Salmonella enterica serovar Typhimurium and E. coli O157:H7 at 10(-1) to 106 CFU/g or CFU/ml, respectively. Samples were blended (sprouts only) and then centrifuged at high speed to sediment the total bacterial population. The precipitate was processed for DNA isolation, PCR amplification, and amplicon confirmation by Southern hybridization. Mean pathogen recoveries after centrifugation ranged from 96 to 99% for both pathogens in both matrices. Using primers targeting the invA gene for Salmonella Typhimurium and the stx genes of E. coli O157:H7, it was possible to detect both pathogens in alfalfa sprouts at seeding concentrations as low as 10 CFU/g. PCR detection limits for both pathogens from spent irrigation water were 10(-1) CFU/ml, the equivalent of 100 CFU/liter of water. Because spent irrigation water is constitutionally simple, it is particularly well suited for bacterial concentration by simple centrifugation steps. In this study, progress was made toward development of a rapid, inexpensive, and sensitive method for the detection of sprout-associated pathogens that is relevant to current industrial practices and needs.
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Affiliation(s)
- Lynette M Johnston
- Department of Food Science, College of Life Science and Agriculture, North Carolina State University, Raleigh, North Carolina 27695-7624, USA
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