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Devanathan N, Mukhopadhyay HK, Sihag KK, Terence Nathan A, Chakkaravarthi A, Srinivasan L, Srinivas MV, Vasu J, Shanmugam VP, Rahi M, Devaraju P. Synanthropic rodents and shrews are reservoirs of zoonotic bacterial pathogens and act as sentinels for antimicrobial resistance spillover in the environment: A study from Puducherry, India. One Health 2024; 18:100759. [PMID: 38784598 PMCID: PMC11111835 DOI: 10.1016/j.onehlt.2024.100759] [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: 02/15/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024] Open
Abstract
Antimicrobial resistance (AMR) is a global public health concern and needs to be monitored for control. In this study, synanthropic rodents trapped from humans and animal habitats in Puducherry, India, were screened as sentinels for bacterial pathogens of public health importance and antimicrobial resistance spillover. From the trapped rodents and shrews (n = 100) pathogens viz., Staphylococcus sp, E. coli and Salmonella sp were isolated from oropharyngeal and rectal swabs on Mannitol salt, Mac Conkey and Xylose lysine deoxycholate media respectively. The AMR genes in these isolates were screened by PCR. A total of 76, S. aureus and 19, Staphylococcus non aureus were isolated. E. coli was isolated in 89 samples and among the Salmonella sp (n = 59), 16, were S. enteritidis and 29, were S. typhimurium. A total of 46 MRSA isolates with mec A (n = 40) and mec C (n = 6) were detected. Also, 36.84% and 5.3% Staphylococcus non aureus isolates were tested to have mec A and mec C genes. AMR genes encoding ESBL [blaTEM in 21, blaSHV in 45 and blaCTX-M in 11] was tested positive in 77 E. coli isolates. Among, Salmonella isolates 44/45 were screened to have AMR genes [tet in 13, sul3 & sul4 in 20 and qnrA in 11]. Antibiotic sensitivity test confirmed the antimicrobial resistance. Isolation of pathogens of public health importance and demonstration of genetic elements conferring antimicrobial resistance in the synanthropic rodents confirms that they act as reservoirs and appropriate sentinels to monitor AMR spillover in the environment.
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Affiliation(s)
- Nivedha Devanathan
- Department of Veterinary Microbiology, Rajiv Gandhi Institute of Veterinary Education and Research (RIVER), Kurumbapet, Puducherry 605009, India
| | - Hirak Kumar Mukhopadhyay
- Department of Veterinary Microbiology, Rajiv Gandhi Institute of Veterinary Education and Research (RIVER), Kurumbapet, Puducherry 605009, India
| | - Krishan Kumar Sihag
- Unit of One Health, ICMR- Vector Control Research Centre (ICMR-VCRC), Indira Nagar, Puducherry 605006, India
| | - A. Terence Nathan
- Unit of One Health, ICMR- Vector Control Research Centre (ICMR-VCRC), Indira Nagar, Puducherry 605006, India
| | - Aravindasamy Chakkaravarthi
- Unit of One Health, ICMR- Vector Control Research Centre (ICMR-VCRC), Indira Nagar, Puducherry 605006, India
| | - Lakshmy Srinivasan
- Unit of One Health, ICMR- Vector Control Research Centre (ICMR-VCRC), Indira Nagar, Puducherry 605006, India
| | - Mouttou Vivek Srinivas
- Department of Veterinary Microbiology, Rajiv Gandhi Institute of Veterinary Education and Research (RIVER), Kurumbapet, Puducherry 605009, India
| | - Jayalakshmi Vasu
- Department of Veterinary Microbiology, Rajiv Gandhi Institute of Veterinary Education and Research (RIVER), Kurumbapet, Puducherry 605009, India
| | - Venkatesa Perumal Shanmugam
- Department of Veterinary Biochemistry, Rajiv Gandhi Institute of Veterinary Education and Research (RIVER), Kurumbapet, Puducherry 605009, India
| | - Manju Rahi
- The Director, ICMR- Vector Control Research Centre (ICMR-VCRC), Indira Nagar, Puducherry 605006, India
| | - Panneer Devaraju
- Unit of One Health, ICMR- Vector Control Research Centre (ICMR-VCRC), Indira Nagar, Puducherry 605006, India
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Zhang H, Laššáková S, Yan Z, Wang X, Šenkyřík P, Gaňová M, Chang H, Korabecna M, Neuzil P. Digital polymerase chain reaction duplexing method in a single fluorescence channel. Anal Chim Acta 2022; 1238:340243. [DOI: 10.1016/j.aca.2022.340243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 07/28/2022] [Accepted: 08/02/2022] [Indexed: 11/24/2022]
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Grembi JA, Mayer-Blackwell K, Luby SP, Spormann AM. High-Throughput Multiparallel Enteropathogen Detection via Nano-Liter qPCR. Front Cell Infect Microbiol 2020; 10:351. [PMID: 32766166 PMCID: PMC7381150 DOI: 10.3389/fcimb.2020.00351] [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: 01/17/2020] [Accepted: 06/08/2020] [Indexed: 11/13/2022] Open
Abstract
Quantitative molecular diagnostic methods can effectively detect pathogen-specific nucleic acid sequences, but costs associated with multi-pathogen panels hinder their widespread use in research trials. Nano-liter qPCR (nL-qPCR) is a miniaturized tool for quantification of multiple targets in large numbers of samples based on assay parallelization on a single chip, with potentially significant cost-savings due to rapid throughput and reduced reagent volumes. We evaluated a suite of novel and published assays to detect 17 enteric pathogens using a commercially available nL-qPCR technology. Amplification efficiencies ranged from 88 to 98% (mean 91%) and were reproducible across four operators at two separate facilities. When applied to fecal material, assays were sensitive and selective (99.8% of DNA amplified were genes from the target organism). Due to nanofluidic volumes, detection limits were 1-2 orders of magnitude less sensitive for nL-qPCR than an enteric TaqMan Array Card (TAC). However, higher detection limits do not hinder detection of diarrhea-causing pathogen concentrations. Compared to TAC, nL-qPCR displayed 99% (95% CI 0.98, 0.99) negative percent agreement and 62% (95% CI 0.59, 0.65) overall positive percent agreement for presence of pathogens across diarrheal and non-diarrheal fecal samples. Positive percent agreement was 89% among samples with concentrations above the nL-qPCR detection limits. nL-qPCR assays showed an underestimation bias of 0.34 log10 copies/gram of stool [IQR -0.40, -0.28] compared with TAC. With 12 times higher throughput for a sixth of the per-sample cost of the enteric TAC, the nL-qPCR chip is a viable alternative for enteropathogen quantification for studies where other technologies are cost-prohibitive.
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Affiliation(s)
- Jessica A Grembi
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, United States
| | - Koshlan Mayer-Blackwell
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, United States
| | - Stephen P Luby
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, CA, United States
| | - Alfred M Spormann
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, United States.,Department of Chemical Engineering, Stanford University, Stanford, CA, United States
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Paniel N, Noguer T. Detection of Salmonella in Food Matrices, from Conventional Methods to Recent Aptamer-Sensing Technologies. Foods 2019; 8:E371. [PMID: 31480504 PMCID: PMC6770675 DOI: 10.3390/foods8090371] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/20/2019] [Accepted: 08/26/2019] [Indexed: 01/01/2023] Open
Abstract
Rapid detection of the foodborne pathogen Salmonella in food processing is of crucial importance to prevent food outbreaks and to ensure consumer safety. Detection and quantification of Salmonella species in food samples is routinely performed using conventional culture-based techniques, which are labor intensive, involve well-trained personnel, and are unsuitable for on-site and high-throughput analysis. To overcome these drawbacks, many research teams have developed alternative methods like biosensors, and more particularly aptasensors, were a nucleic acid is used as biorecognition element. The increasing interest in these devices is related to their high specificity, convenience, and relative rapid response. This review aims to present the advances made in these last years in the development of biosensors for the detection and the quantification of Salmonella, highlighting applications on meat from the chicken food chain.
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Affiliation(s)
- Nathalie Paniel
- Laboratoire BAE, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France.
- Unité EMaiRIT'S, Centre Technique de la Conservation des Produits Agricoles (CTCPA), Site Agroparc, 449 Avenue Clément Ader, BP21203, 84911 Avignon, France.
| | - Thierry Noguer
- Laboratoire BAE, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France.
- Laboratoire de Biodiversité et Biotechnologies Microbiennes, USR 3579, Sorbonne Universités (UPMC) Paris 6 et CNRS, Observatoire Océanologique, 66650 Banyuls-sur-Mer, France.
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Xie Y, Qiu N, Wang G. Toward a better guard of coastal water safety-Microbial distribution in coastal water and their facile detection. MARINE POLLUTION BULLETIN 2017; 118:5-16. [PMID: 28215556 DOI: 10.1016/j.marpolbul.2017.02.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 01/19/2017] [Accepted: 02/09/2017] [Indexed: 06/06/2023]
Abstract
Prosperous development in marine-based tourism has raised increasing concerns over the sanitary quality of coastal waters with potential microbial contamination. The World Health Organization has set stringent standards over a list of pathogenic microorganisms posing potential threats to people with frequent coastal water exposure and has asked for efficient detection procedures for pathogen facile identification. Inspection of survey events regarding the occurrence of marine pathogens in recreational beaches in recent years has reinforced the need for the development of a rapid identification procedure. In this review, we examine the possibility of recruiting uniform molecular assays to identify different marine pathogens and the feasibility of appropriate biomarkers, including enterochelin biosynthetic genes, for general toxicity assays. The focus is not only on bacterial pathogens but also on other groups of infectious pathogens. The ultimate goal is the development of a handy method to more efficiently and rapidly detect marine pathogens.
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Affiliation(s)
- Yunxuan Xie
- Tianjin University Center for Marine Environmental Ecology, School of Environmental Science & Engineering, Tianjin University, Tianjin 300072, China
| | - Ning Qiu
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Guangyi Wang
- Tianjin University Center for Marine Environmental Ecology, School of Environmental Science & Engineering, Tianjin University, Tianjin 300072, China.
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Chiang YC, Wang HH, Ramireddy L, Chen HY, Shih CM, Lin CK, Tsen HY. Designing a biochip following multiplex polymerase chain reaction for the detection of Salmonella serovars Typhimurium, Enteritidis, Infantis, Hadar, and Virchow in poultry products. J Food Drug Anal 2017; 26:58-66. [PMID: 29389589 PMCID: PMC9332633 DOI: 10.1016/j.jfda.2016.11.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/03/2016] [Accepted: 11/21/2016] [Indexed: 11/29/2022] Open
Abstract
Salmonella-contaminated foods, especially poultry-derived foods (eggs, chicken meat), are the major source of salmonellosis. Not only in the European Union (EU), but also in the United States, Japan, and other countries, has salmonellosis been an issue of concern for food safety control agencies. In 2005, EU regulation 1003/2005 set a target for the control and reduction of five target Salmonella enterica serovars—S. Typhimurium, S. Enteritidis, S. Infantis, S. Hadar, and S. Virchow—in breeding flocks. Thus, a simple biochip for the rapid detection of any of these five Salmonella serovars in poultry products may be required. The objectives of this study were to design S. Virchow-specific primers and to develop a biochip for the simultaneous identification of all or any of these five Salmonella serovars in poultry and poultry products. Experimentally, we designed novel polymerase chain reaction (PCR) primers for the specific detection of S. Virchow, S. Infantis, and S. Hadar. The specificity of all these primers and two known primer sets for S. Typhimurium and S. Enteritidis was then confirmed under the same PCR conditions using 57 target strains and 112 nontarget Salmonella strains as well as 103 non-Salmonella strains. Following multiplex PCR, strains of any of these five Salmonella serovars could be detected by a chromogenic biochip deployed with DNA probes specific to these five Salmonella serovars. In comparison with the multiplex PCR methods, the biochip assay could improve the detection limit of each of the Salmonella serovars from N × 103 cfu/mL to N × 102 cfu/mL sample in either the pure culture or the chicken meat samples. With an 8-hour enrichment step, the detection limit could reach up to N × 100 cfu/mL.
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Affiliation(s)
- Yu-Cheng Chiang
- Department of Food Science and Technology, Hung Kuang University, Number 1018, Section 6, Taiwan Boulevard, Shalu District, Taichung City 43302, Taiwan, ROC.
| | - Hsien-Huang Wang
- DR. Chip Biotech, Science-Based Industrial Park, Chu-Nan, Miao-Li County 350, Taiwan, ROC
| | - Latha Ramireddy
- Department of Food Science and Technology, Hung Kuang University, Number 1018, Section 6, Taiwan Boulevard, Shalu District, Taichung City 43302, Taiwan, ROC
| | - Hsin-Yen Chen
- Department of Food Science and Technology, Hung Kuang University, Number 1018, Section 6, Taiwan Boulevard, Shalu District, Taichung City 43302, Taiwan, ROC
| | - Chia-Ming Shih
- Department of Food Science and Technology, Hung Kuang University, Number 1018, Section 6, Taiwan Boulevard, Shalu District, Taichung City 43302, Taiwan, ROC
| | - Chien-Ku Lin
- Department of Food Science and Technology, Hung Kuang University, Number 1018, Section 6, Taiwan Boulevard, Shalu District, Taichung City 43302, Taiwan, ROC
| | - Hau-Yang Tsen
- Department of Food Science and Technology, Hung Kuang University, Number 1018, Section 6, Taiwan Boulevard, Shalu District, Taichung City 43302, Taiwan, ROC.
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Ogunremi D, Nadin-Davis S, Dupras AA, Márquez IG, Omidi K, Pope L, Devenish J, Burke T, Allain R, Leclair D. Evaluation of a Multiplex PCR Assay for the Identification of Salmonella Serovars Enteritidis and Typhimurium Using Retail and Abattoir Samples. J Food Prot 2017; 80:295-301. [PMID: 28221989 DOI: 10.4315/0362-028x.jfp-16-167] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A multiplex PCR was developed to identify the two most common serovars of Salmonella causing foodborne illness in Canada, namely, serovars Enteritidis and Typhimurium. The PCR was designed to amplify DNA fragments from four Salmonella genes, namely, invA gene (211-bp fragment), iroB gene (309-bp fragment), Typhimurium STM 4497 (523-bp fragment), and Enteritidis SE147228 (612-bp fragment). In addition, a 1,026-bp ribosomal DNA (rDNA) fragment universally present in bacterial species was included in the assay as an internal control fragment. The detection rate of the PCR was 100% among Salmonella Enteritidis (n = 92) and Salmonella Typhimurium (n = 33) isolates. All tested Salmonella isolates (n = 194) were successfully identified based on the amplification of at least one Salmonella -specific DNA fragment. None of the four Salmonella DNA amplicons were detected in any of the non- Salmonella isolates (n = 126), indicating an exclusivity rate of 100%. When applied to crude extracts of 2,001 field isolates of Salmonella obtained during the course of a national microbiological baseline study in broiler chickens and chicken products sampled from abattoir and retail outlets, 163 isolates, or 8.1%, tested positive for Salmonella Enteritidis and another 80 isolates, or 4.0%, tested as Salmonella Typhimurium. All isolates identified by serological testing as Salmonella Enteritidis in the microbiological study were also identified by using the multiplex PCR. The new test can be used to identify or confirm pure isolates of the two serovars and is also amenable for integration into existing culture procedures for accurate detection of Salmonella colonies.
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Affiliation(s)
- Dele Ogunremi
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario, Canada K2H 8P9
| | - Susan Nadin-Davis
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario, Canada K2H 8P9
| | - Andrée Ann Dupras
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario, Canada K2H 8P9
| | - Imelda Gálvan Márquez
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario, Canada K2H 8P9
| | - Katayoun Omidi
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario, Canada K2H 8P9
| | - Louise Pope
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario, Canada K2H 8P9
| | - John Devenish
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario, Canada K2H 8P9
| | - Teresa Burke
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario, Canada K2H 8P9
| | - Ray Allain
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario, Canada K2H 8P9
| | - Daniel Leclair
- Food Safety Science Division, Floor 5, 1400 Merivale Road, Tower 2, Ottawa, Ontario, Canada K1A 0Y9
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Akiba M, Kusumoto M, Iwata T. Rapid identification of Salmonella enterica serovars, Typhimurium, Choleraesuis, Infantis, Hadar, Enteritidis, Dublin and Gallinarum, by multiplex PCR. J Microbiol Methods 2011; 85:9-15. [PMID: 21329737 DOI: 10.1016/j.mimet.2011.02.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 01/28/2011] [Accepted: 02/04/2011] [Indexed: 10/18/2022]
Abstract
Salmonella enterica subsp. enterica poses a threat to both human and animal health, with more than 2500 serovars having been reported to date. Salmonella serovars are identified by slide and tube agglutination tests using O and H antigen-specific anti-sera, although this procedure is both labor intensive and time consuming. Establishment of a method for rapid screening of the major Salmonella serovars is therefore required. We have established multiplex polymerase chain reaction (m-PCR) assays for identification of seven serovars of Salmonella, i.e., Typhimurium, Choleraesuis, Infantis, Hadar, Enteritidis, Dublin and Gallinarum. Three serovar-specific genomic regions (SSGRs) of each serovar were selected using an approach in comparative genomics. The Salmonella-specific invA gene was used to confirm the genetic background of the organisms. The isolates tested were identified as a target serovar when the three selected SSGRs and invA were all positive for amplification. The specificity of each m-PCR assay was investigated using 118 serovars of Salmonella and 12 species of non-Salmonella strains. Although a small number of false-positive results were observed in the m-PCR assays used to identify Typhimurium, Choleraesuis, Enteritidis and Dublin for closely related serovars, false-negative results were not observed in any assays. These assays had sufficient specificity to identify the seven Salmonella serovars, and therefore, have the potential for use as rapid screening methods.
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Affiliation(s)
- Masato Akiba
- Safety Research Team, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba 305-0856, Japan.
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Malcomson RD, McCullough CT, Bruce DJ, Harrison DJ. The scope of quantitative polymerase chain reaction assays in clinical molecular pathology. Mol Pathol 2010; 48:M178-83. [PMID: 16696001 PMCID: PMC407957 DOI: 10.1136/mp.48.4.m178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- R D Malcomson
- Department of Pathology, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG
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Nde CW, Fakhr MK, Doetkott C, Logue CM. An evaluation of conventional culture, invA PCR, and the real-time PCR iQ-Check kit as detection tools for Salmonella in naturally contaminated premarket and retail turkey. J Food Prot 2008; 71:386-91. [PMID: 18326192 DOI: 10.4315/0362-028x-71.2.386] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study was aimed at comparing the ability of conventional culture, the iQ-Check real-time PCR kit, and invA PCR to detect Salmonella in naturally contaminated premarket and retail turkey parts. Premarket (n = 120) turkey parts collected from a commercial turkey processing plant, and retail turkey parts (n = 138) were examined. Both PCR methods detected a significantly greater (P < 0.05) number of positive samples when compared with the conventional culture method for the premarket turkey parts. The indices of total agreement between the conventional culture method and the iQ-Check kit for the premarket and retail parts were 79.2% (95% CI: 70.8, 86) and 90.6% (95% CI: 84.4, 94.9), respectively. When the conventional culture method was compared with invA PCR for Salmonella detection in the premarket and retail parts, the indices of total agreement were 75.8% (95% CI: 67.2, 83.2) and 84.1% (95% CI: 76.9, 89.7), respectively. The rates of false positives (premarket: 31.9%, retail: 9.7%) and false negatives (premarket: 5.9%, retail: 9.7%) were determined between the culture method and the iQ-Check kit. When invA PCR was compared with the culture method, the rates of false positives (premarket: 37.7%, retail: 11.1%) and false negatives (premarket: 5.9%, retail: 18.3%) were obtained. The higher total agreement and the lower rates of both false positives and false negatives for the iQ-Check kit compared with invA PCR for both premarket and retail turkey parts corroborates the use of the iQ-Check kit as a screening tool for Salmonella in poultry meat.
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Affiliation(s)
- Chantal W Nde
- The Great Plains Institute of Food Safety, Department of Veterinary and Microbiological Sciences, 1523 Centennial Boulevard, 130A Van Es Hall, North Dakota State University, Fargo, North Dakota 58105, USA
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Trafny EA, Kozłowska K, Szpakowska M. A novel multiplex PCR assay for the detection of Salmonella enterica serovar Enteritidis in human faeces. Lett Appl Microbiol 2007; 43:673-9. [PMID: 17083715 DOI: 10.1111/j.1472-765x.2006.02007.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To develop a multiplex PCR assay for the detection of Salmonella enterica serovar Enteritidis in human faeces. METHODS AND RESULTS A total of 54 Salmonella strains representing 19 serovars and non-Salmonella strains representing 11 different genera were used. Five primer pairs were employed in the assay. Three of them targeted to the genes hilA, spvA and invA that encode virulence-associated factors. A fourth primer pair amplified a fragment of a unique sequence within S. enterica serovar Enteritidis genomes. An internal amplification control (a fragment of a conservative sequence within the 16S rRNA genes) was targeted by a fifth primer pair. The assay produced two or three amplicons from the invA, hilA and 16S rRNA genes for 19 Salmonella serovars. All Salmonella and non-Salmonella strains yielded a band of an internal amplification control. For S. enterica serovar Typhimurium, four products (the fourth from the spvA gene), and for S. enterica serovar Enteritidis five amplicons (the fifth from the sdf gene) were observed. S. enterica serovar Enteritidis was cultured from three of 71 rectal swabs from diarrhoeal patients. Five specific amplicons were generated with the multiplex PCR assay only from culture-positive faecal samples. CONCLUSION The multiplex PCR assay specifically detects S. enterica serovar Enteritidis. SIGNIFICANCE AND IMPACT OF THE STUDY This is a novel multiplex PCR assay, which contains an internal amplification control and enables concurrent survey for Salmonella virulence genes.
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Affiliation(s)
- E A Trafny
- Department of Microbiology and Epidemiology, Military Institute of Hygiene and Epidemiology, Warsaw, Poland.
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Imre A, Olasz F, Nagy B. Development of a PCR system for the characterisation of Salmonella flagellin genes. Acta Vet Hung 2005; 53:163-72. [PMID: 15959975 DOI: 10.1556/avet.53.2005.2.2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Analysis of flagellin genes was carried out on strains of Salmonella Typhimurium, Salmonella Hadar, Salmonella Abortusequi, Salmonella Enteritidis and Salmonella Gallinarum serovars, using a PCR system designed in this study. The purpose of these studies was to explore the flagellin genes of biphasic and monophasic Salmonellae for future targeted genetic interventions. The PCR primers were designed for two different structural genes of flagellin (fliC, fljB), for the repressor of fliC (fljA), for the operator region of fliC, and for the invertase system responsible for phase variation in Salmonella (hin, hixL, hixR). PCR analysis revealed that all of the examined genes (fliC, fliC-operator, fljB, fljA, hin, hixL, hixR) were present in all S. Typhimurium (n = 10) and S. Hadar (n = 10) strains tested. The results obtained on S. Typhimurium and S. Hadar strains confirmed their biphasic character at DNA level. However, the S. Enteritidis (n = 46) and S. Gallinarum (n = 5) strains lacked the invertase system (hin, hixL, hixR) as well as the fljA and fljB genes, while fliC and its operator were detectable. Consequently, the S. Enteritidis strains could only express fliC gene resulting in phase H1 flagellin. The examined S. Gallinarum strains were also demonstrated to have a cryptic flagellin gene (fliC). On the other hand, PCR results on S. Abortusequi (n = 2) indicated that both flagellin genes (fliC, fljB) and the whole phase variation system were present in both strains tested but only the H2 phase gene (fljB) was expressed. The phenotype of these strains could be clarified by motility test and/or by classical flagellar serology. The findings are also substantiated by the results of serovar-specific PCR for S. Typhimurium and S. Enteritidis. In conclusion, the PCR system developed in this study proved to be suitable for characterisation of Salmonella flagellin genes and confirmed serological results regarding all S. Typhimurium, S. Hadar and S. Enteritidis strains. This system could also identify cryptic flagellar genes of S. Abortusequi and S. Gallinarum.
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Affiliation(s)
- A Imre
- Veterinary Medical Research Institute of the Hungarian Academy of Sciences, H-1581 Budapest, PO Box 18, Hungary
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Seo KH, Valentin-Bon IE, Brackett RE, Holt PS. Rapid, specific detection of Salmonella Enteritidis in pooled eggs by real-time PCR. J Food Prot 2004; 67:864-9. [PMID: 15151219 DOI: 10.4315/0362-028x-67.5.864] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An assay was developed for the specific detection of Salmonella Enteritidis in eggs with the use of an application of the fluorogenic 5' nuclease assay (TaqMan). In this assay, a segment of the gene sefA specific to Salmonella group D strains such as Salmonella Enteritidis was used. The amplification of the target gene products was monitored in real-time by incorporating a fluorescent dye-labeled gene-specific probe in the PCR reaction. This method correctly detected and distinguished Salmonella Enteritidis from nearly 50 of non-group D Salmonella and other non-Salmonella strains. Detection of the sefA gene was linear for DNA extracted from approximately 10(2) to 10(9) CFU/ml in phosphate-buffered saline and 10(3) to 10(8) CFU/ml in raw egg. In two trials, when applied to detection of Salmonella Enteritidis in homogenized egg pools and compared with conventional culture methods, the newly developed PCR method yielded a 100% correlation with results obtained by a conventional culture method. However, the PCR method required only 2 days, compared to the 5 days required by the culture method. The sensitivity of this assay was approximately less than 1 CFU/600 g of egg pool. The real-time PCR assay proved to be a rapid, highly sensitive test for detection and quantification of low concentrations of Salmonella Enteritidis in egg samples.
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Affiliation(s)
- K H Seo
- U.S. Food and Drug Administration, CFSAN/OPDFB, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA.
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Agron PG, Walker RL, Kinde H, Sawyer SJ, Hayes DC, Wollard J, Andersen GL. Identification by subtractive hybridization of sequences specific for Salmonella enterica serovar enteritidis. Appl Environ Microbiol 2001; 67:4984-91. [PMID: 11679316 PMCID: PMC93261 DOI: 10.1128/aem.67.11.4984-4991.2001] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Salmonella enterica serovar Enteritidis, a major cause of food poisoning, can be transmitted to humans through intact chicken eggs when the contents have not been thoroughly cooked. Infection in chickens is asymptomatic; therefore, simple, sensitive, and specific detection methods are crucial for efforts to limit human exposure. Suppression subtractive hybridization was used to isolate DNA restriction fragments present in Salmonella serovar Enteritidis but absent in other bacteria found in poultry environments. Oligonucleotide primers to candidate regions were used in polymerase chain reactions to test 73 non-Enteritidis S. enterica isolates comprising 34 different serovars, including Dublin and Pullorum, two very close relatives of Enteritidis. A primer pair to one Salmonella difference fragment (termed Sdf I) clearly distinguished serovar Enteritidis from all other serovars tested, while two other primer pairs only identified a few non-Enteritidis strains. These primer pairs were also useful for the detection of a diverse collection of clinical and environmental Salmonella serovar Enteritidis isolates. In addition, five bacterial genera commonly found with Salmonella serovar Enteritidis were not detected. By treating total DNA with an exonuclease that degrades sheared chromosomal DNA but not intact circular plasmid DNA, it was shown that Sdf I is located on the chromosome. The Sdf I primers were used to screen a Salmonella serovar Enteritidis genomic library and a unique 4,060-bp region was defined. These results provide a basis for developing a rapid, sensitive, and highly specific detection system for Salmonella serovar Enteritidis and provide sequence information that may be relevant to the unique characteristics of this serovar.
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Affiliation(s)
- P G Agron
- Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
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Szabo EA, Mackey BM. Detection of Salmonella enteritidis by reverse transcription-polymerase chain reaction (PCR). Int J Food Microbiol 1999; 51:113-22. [PMID: 10574087 DOI: 10.1016/s0168-1605(99)00106-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A reverse transcription-polymerase chain reaction (RT-PCR) method was developed for detecting mRNA from the sefA gene of Salmonella enteritidis. Detection of target mRNA was examined from cells grown in buffered peptone water at different temperatures (37, 25 and 15 degrees C) and pH (5.5, 7.2 and 8.5). The results revealed that the levels of transcription of the sefA gene differed depending upon the physiological state of the cells. This affected the sensitivity of the RT-PCR assay. When the assay was evaluated for the detection of S. enteritidis PT4 in artificially contaminated minced beef and whole egg samples, an enrichment step was used (buffered peptone water, pH 7.2, 37 degrees C, 16 h) to increase the sensitivity of the assay. In the presence of the normal background flora of each food type, it was possible to detect ten cells of S. enteritidis PT4 after a 16-h enrichment using the RT-PCR assay, with a total testing time of 28 h. Unlike the PCR test for the sefA gene that was tested in parallel, the RT-PCR assay did not detect nonviable (heat-inactivated) S. enteritidis PT4 cells. The results supported the usefulness of RT-PCR as a method for the detection of viable microorganisms.
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Affiliation(s)
- E A Szabo
- Food Science Australia, North Ryde Laboratory, NSW, Australia
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Soumet C, Ermel G, Rose N, Rose V, Drouin P, Salvat G, Colin P. Evaluation of a multiplex PCR assay for simultaneous identification of Salmonella sp., Salmonella enteritidis and Salmonella typhimurium from environmental swabs of poultry houses. Lett Appl Microbiol 1999; 28:113-7. [PMID: 10063640 DOI: 10.1046/j.1365-2672.1999.00488.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A Multiplex PCR-based assay (m-PCR) with three sets of primers was developed for the detection of all serotypes of Salmonella enterica and the identification of Salmonella Enteritidis and Salmonella Typhimurium. This method was evaluated against a bacteriological method for the analysis of environmental swabs of poultry houses. Samples were preenriched in phosphate-buffered peptone water for 24 h and subjected to three different protocols prior to PCR: (i) an immunomagnetic separation using Dynabeads anti-Salmonella (Dynal); (ii) a DNA extraction procedure using the Instagene matrix; (iii) an additional step of culture on an MSRV medium. With protocols 1 and 2, eight positive results were found by PCR and 20 with the bacteriological method. Protocol 3 combining MSRV and PCR gave similar results to those obtained from bacteriological methods and allowed Salmonella detection within 2 days.
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Affiliation(s)
- C Soumet
- Unité d'Hygiène et Qualité des Produits Avicoles et Porcins, Centre National d'Etudes Vétérinaires et Alimentaires Zoopôle-Beaucemaine-Les Croix, Ploufragan, France
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Abstract
The polymerase chain reaction (PCR) is a nucleic acid-based technique that enables the rapid and sensitive detection of specific micro-organisms. Although this technique is widely used in veterinary research, it has not yet found applications in routine microbiological analysis of veterinary clinical samples. However, advances in sample preparation together with the increasing availability of specific gene sequences will probably lead to the more widespread diagnostic use of PCR in the future. PCR is likely to have a strong impact in the epidemiology, treatment and prevention of animal infectious diseases.
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Affiliation(s)
- J M Rodriguez
- Departamento de Nutrición y Bromatología III, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain
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Woodward MJ, Kirwan SE. Detection of Salmonella enteritidis in eggs by the polymerase chain reaction. Vet Rec 1996; 138:411-3. [PMID: 8733179 DOI: 10.1136/vr.138.17.411] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A polymerase chain reaction (PCR) for the specific detection of the gene sequence, sefA, encoded by all isolates of Salmonella enteritidis, was developed. The PCR could detect as few as four S enteritidis washed bacterial cells but egg contents inhibited the PCR. Eggs spiked with 50 S enteritidis bacterial cells were homogenised, inoculated into buffered peptone water and grown at 37 degrees C for 16 hours, when the PCR was successful. A positive internal control was developed to differentiate between true and false negative PCR results for the detection of S enteritidis. In a limited trial of the egg handling procedures and the PCR, one of 250 chickens' eggs from retail outlets was found to be contaminated with S enteritidis.
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Affiliation(s)
- M J Woodward
- Bacteriology Department, Central Veterinary Laboratory, Addlestone, Surrey
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Lax AJ, Barrow PA, Jones PW, Wallis TS. Current perspectives in salmonellosis. THE BRITISH VETERINARY JOURNAL 1995; 151:351-77. [PMID: 7552193 DOI: 10.1016/s0007-1935(95)80126-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Salmonellosis remains an important human and animal problem worldwide and, despite extensive research effort, many of the details of its pathogenesis are not known. While there have been recent advances in some aspects of pathogenesis, other areas are not understood. The host adaptation shown by several serotypes and the recent dramatic changes in the predominance of particular serotypes are examples. Molecular techniques using in vitro model systems have identified several genes involved in adhesion and invasion, though their function and even their relevance to disease remain poorly defined. Similarly, several potential toxins have been identified and the genes cloned, although their significance is far from clear. Some of the essential genes on the large virulence plasmids have been defined, and these are known to be necessary for the establishment of systemic infection. Two of these genes are regulatory, but the function of the other genes is unknown. A general theme has been the identification of gene systems involved in regulation of virulence. New vaccines, based on 'rational attenuation' are being designed, and these have also been used to carry heterologous antigens; such vaccines are currently undergoing trials. The improved understanding of the pathogenesis of salmonellosis may also provide a model of wide applicability to a more general understanding of bacterial pathogenesis. New techniques, including the polymerase chain reaction, are being applied to diagnose salmonellosis.
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Affiliation(s)
- A J Lax
- Institute for Animal Health, Compton, Newbury, Berkshire, UK
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