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Das D, Chen WL, Chuang HS. Rapid and Sensitive Pathogen Detection by DNA Amplification Using Janus Particle-Enabled Rotational Diffusometry. Anal Chem 2021; 93:13945-13951. [PMID: 34618421 DOI: 10.1021/acs.analchem.1c03209] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rapid and sensitive detection of infectious bacteria is in all-time high demand to prevent the further spread of the infection and allow early medical intervention. In this study, we use rotational diffusometry (RD), a natural phenomenon characterized by Janus particles, to detect pathogens like Escherichia coli by performing amplification of specific genes. This biosensing method is used to measure the change in viscosity of the fluid in the presence and absence of DNA in the solution by capturing images of modified microbeads at 10 Hz by a CCD camera followed by cross-correlation algorithm analysis. Using rotational diffusometry, we have achieved E. coli detection with 50 pg/μL DNA with a measurement time of 30 s and a sample volume of 2 μL. This sensitivity was achieved with 30 thermal cycles for three different amplicons, viz., 84, 147, and 246 bp. Meanwhile, in the case of 10 and 20 thermal cycles, the detection sensitivity was achieved with 0.1 and 1 ng/μL DNA concentrations for a 246 bp amplicon. Compared with conventional PCR, this technique appears to improve the detection time, thereby reaching a turnaround time of less than 60 min. Other studies showed a successful identification of DNA amplification up to 10 thermal cycles with different sizes of amplicons. The effect of DNA concentration, amplicon size, and the number of thermal cycles on the detection of E. coli was examined in detail and represented in the form of three maps. These maps show the clear difference and the advantages of RD method in comparison with conventional PCR. This unconventional and rapid biosensing method can be used further for downstream application of nucleic acid amplification-based pathogen detection and early disease control.
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Affiliation(s)
- Dhrubajyoti Das
- Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Wei-Long Chen
- Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Han-Sheng Chuang
- Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.,Medical Device Innovation Center, National Cheng Kung University, Tainan 701, Taiwan
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Nagai H, Tomioka K, Okumura S. Optimal Conditions for the Asymmetric Polymerase Chain Reaction for Detecting Food Pathogenic Bacteria Using a Personal SPR Sensor. Appl Biochem Biotechnol 2018; 187:323-337. [PMID: 29943274 DOI: 10.1007/s12010-018-2819-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 06/10/2018] [Indexed: 12/16/2022]
Abstract
We have been developing quick and simple system for detecting food-poisoning bacteria using a combination of an asymmetric PCR and a portable surface plasmon resonance (SPR) sensor. The system would be suitable for point-of-care detection of food-poisoning bacteria in the field of food industry. In this study, we established a novel method for quantifying the amplified forward (F) and reverse (R) chains of Staphylococcus aureus separately by high-performance liquid chromatography (HPLC). The concentration of single-stranded DNA amplicon excessively amplified, which is crucial for the system, could be calculated as the difference between those of the F- and R-chains. For the R-chain, a correction based on the F-chain concentration in the sample was used to obtain a more accurate value, because the determination of the R-chain concentration was affected by that of the coexisting F-chain. The concentration values were also determined by fluorescence imaging for electrophoresis gels of amplicons with FITC- or Cy5-conjugated primers, and they were in good agreement with the values by the HPLC. The measured concentration of the single-strand F-chain correlated well with the value of the SPR response against the probe that was a complementary sequence of the F-chain, immobilized on the sensor chip of the SPR sensor.
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Affiliation(s)
- Haruka Nagai
- Department of Biochemistry and Applied Chemistry, National Institute of Technology, Kurume College, 1-1-1 Komorino, Kurume, Fukuoka, 830-8555, Japan
| | - Kanji Tomioka
- Department of Biochemistry and Applied Chemistry, National Institute of Technology, Kurume College, 1-1-1 Komorino, Kurume, Fukuoka, 830-8555, Japan
| | - Shiro Okumura
- Biotechnology and Food Research Institute, Fukuoka Industrial Technology Center, 1465-5 Aikawa, Kurume, Fukuoka, 839-0861, Japan.
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Simultaneous detection of three foodborne pathogenic bacteria in food samples by microchip capillary electrophoresis in combination with polymerase chain reaction. J Chromatogr A 2018; 1555:100-105. [DOI: 10.1016/j.chroma.2018.04.058] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 04/23/2018] [Accepted: 04/25/2018] [Indexed: 11/22/2022]
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RAJASHEKHARA DB, FAIROZE MDNADEEM, KARABASANAVAR NAGAPPA, MADHAVAPRASAD CB, SHILPA AG, KOTRESH AM, BAGALKOTE PRASHANTHS, NADOOR PRAKASH. Molecular detection and antibiogram of virulent Salmonellae isolated from chicken meat. THE INDIAN JOURNAL OF ANIMAL SCIENCES 2017. [DOI: 10.56093/ijans.v87i2.67748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Salmonella has emerged as one of the most common and frequent pathogen associated with the food poisoning. In the present study, a total of 240 chicken meat samples were collected from retail markets of Shivamogga region; where, 13 samples were found positive for Salmonella species by genus specific PCR targeting invA virulent gene, giving an overall prevalence of 5.4%. Retail outlets (slaughter-cum-retailing units) that traditionally processed chicken meat showed higher prevalence of 7.5% (n=120); whereas, retail chicken meat originated from organized abattoirs showed prevalence of 3.3% (n=120). Among traditional retail outlets, those retail units processing multiple animal species showed higher prevalence (8.3%, n=60) of Salmonella spp. compared to those that processed chicken meat alone (6.6%, n=60). All the Salmonella species (n=13) isolated from the chicken meat possessed virulence (invA) gene indicating their potential pathogenic mechanisms and also showed varying degree of susceptibility against common antimicrobials (multiple antibiotic resistance index of 0.1176 to 0.3529). High prevalence rate of Salmonella spp. has important public health concern and underscores a need for intense surveillance and monitoring of retail chicken meat and implementation of food quality assurance systems across the chicken supply chain.
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Waithaka PN, Maingi JM, Nyamache AK. Physico-chemical Analysis, Microbial Isolation, Sensitivity Test of the Isolates and Solar Disinfection of Water Running in Community Taps and River Kandutura in Nakuru North Sub-county, Kenya. Open Microbiol J 2015; 9:117-24. [PMID: 26464611 PMCID: PMC4598373 DOI: 10.2174/1874285801509010117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 03/01/2015] [Accepted: 03/06/2015] [Indexed: 11/22/2022] Open
Abstract
Nakuru North sub-county is a peri-urban area which has both dry and wet seasons. Its residents rely mostly on untreated water sources for daily water needs due to unreliable water supply from the urban council. However, this water has not been evaluated on its quality despite residents solely depending on it. This study was aimed at determining the physico-chemical and bacteriological quality of water drawn from River Kandutura and water taps in Nakuru North sub-county. In addition, the study was aimed at carrying out sensitivity test of the isolates to antibiotics and determining effectiveness of solar disinfection in water treatment. A total of 510 water samples; river (255) and taps (255) were collected and analyzed between January and December 2013. Antimicrobial sensitivity test was carried out using Kirby Bauer disk diffusion test. Out of five hundred and ten (510) samples examined for microorganisms, 36.86 % (188/510) were positive for E. coli, Shigella and Salmonella. Water used by Nakuru North sub-county residents is highly contaminated thus posing public health risk. Solar disinfection experiment indicated a possibility of effective decontamination of water up on exposure to sun light for 3-5 h. E. coli showed the highest resistance (26.3 %) followed by Salmonella (17.4 %) while Shigella showed the least (17.1 %). However, there was no significant deference (p=0.98) in resistance among total coliforms, Total heterotrophic and Salmonella at 0.05 level of significant. There is a need to enforce laws and policies on proper waste disposal as part of water pollution control.
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Affiliation(s)
- Paul N Waithaka
- Department of Biological Sciences, St. Joseph’s Kirima School, P. O. Box 17991, Nakuru, Kenya
| | - John Muthini Maingi
- Department of Microbiology, Kenyatta University, P. O. Box 43844, Nairobi, Kenya
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Singh P, Mustapha A. Development of a real-time PCR melt curve assay for simultaneous detection of virulent and antibiotic resistant Salmonella. Food Microbiol 2014; 44:6-14. [DOI: 10.1016/j.fm.2014.04.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 04/04/2014] [Accepted: 04/25/2014] [Indexed: 12/11/2022]
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7
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Zhang J, Wei L, Kelly P, Freeman M, Jaegerson K, Gong J, Xu B, Pan Z, Xu C, Wang C. Detection of Salmonella spp. using a generic and differential FRET-PCR. PLoS One 2013; 8:e76053. [PMID: 24146814 PMCID: PMC3797804 DOI: 10.1371/journal.pone.0076053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 08/17/2013] [Indexed: 11/20/2022] Open
Abstract
To facilitate the detection of Salmonella and to be able to rapidly and conveniently determine the species/subspecies present, we developed and tested a generic and differential FRET-PCR targeting their tetrathionate reductase response regulator gene. The differential pan-Salmonella FRET-PCR we developed successfully detected seven plasmids that contained partial sequences of S. bongori and the six S. enterica subspecies. The detection limit varied from ∼5 copies of target gene/per PCR reaction for S. enterica enterica to ∼200 for S. bongori. Melting curve analysis demonstrated a Tm of ∼68°C for S. enterica enterica, ∼62.5°C for S. enterica houtenae and S. enterica diarizonae, ∼57°C for S. enterica indica, and ∼54°C for S. bongori, S. enterica salamae and S. enterica arizonae. The differential pan-Salmonella FRET-PCR also detected and determined the subspecies of 4 reference strains and 47 Salmonella isolated from clinically ill birds or pigs. Finally, we found it could directly detect and differentiate Salmonella in feline (5/50 positive; 10%; one S. enterica salamae and 4 S. enterica enterica) and canine feces (15/114 positive; 13.2%; all S. enterica enterica). The differential pan-Salmonella FRET-PCR failed to react with 96 non-Salmonella bacterial strains. Our experiments show the differential pan-Salmonella FRET-PCR we developed is a rapid, sensitive and specific method to detect and differentiate Salmonella.
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Affiliation(s)
- Jilei Zhang
- Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu, P. R. China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, P. R. China
| | - Lanjing Wei
- Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu, P. R. China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, P. R. China
| | - Patrick Kelly
- Ross University School of Veterinary Medicine, Basseterre, St. Kitts and Nevis
| | - Mark Freeman
- Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, Virginia, United States of America
| | - Kirsten Jaegerson
- Ross University School of Veterinary Medicine, Basseterre, St. Kitts and Nevis
| | - Jiansen Gong
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, P. R. China
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou, Jiangsu, P. R. China
| | - Bu Xu
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, P. R. China
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou, Jiangsu, P. R. China
| | - Zhiming Pan
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, P. R. China
- Yangzhou University College of Bioscience and Biotechnology, Yangzhou, Jiangsu, P. R. China
| | - Chuanling Xu
- Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu, P. R. China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, P. R. China
| | - Chengming Wang
- Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu, P. R. China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, P. R. China
- * E-mail:
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de Almeida MV, Silva A, Nero LA. Evaluation of target sequences for the polymerase chain reaction-based detection of Salmonella in artificially contaminated beef. Foodborne Pathog Dis 2013; 11:111-8. [PMID: 24102080 DOI: 10.1089/fpd.2013.1623] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Salmonella is a major cause of foodborne diseases worldwide, which has fueled the demand for the development and evaluation of sensitive, specific, and rapid detection methodologies, such as polymerase chain reaction (PCR). In this study, six primer pairs for the detection of Salmonella were evaluated by PCR with isolates of Salmonella spp. (115) and other bacteria (104). The primers designed for the sifB gene provided the best performance regarding specificity and sensitivity (100%). These primers were selected and used to develop a PCR assay for Salmonella detection during the enrichment steps of the conventional detection method in spiked beef samples. The enrichment steps were: buffered peptone water (BPW), Rappaport-Vassiliadis soya broth (RVS) and at the Müller-Kauffmann tetrathionate novobiocin broth (MKTTn), after 18 h (BPW) and 24 h (RVS and MKTTn) of incubation. The initial concentrations of the Salmonella inocula were 10¹, 10², and 10³ colony-forming units/25 g. The protocol was able to detect Salmonella at all concentrations in the enrichment steps, but not in the nonenriched samples. These results indicated that the proposed protocol was suitable to detect Salmonella in beef during the intermediate stages of the conventional isolation protocol, substantially reducing the time required to obtain the final results.
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Tang T, Cheng A, Wang M, Li X, He Q, Jia R, Zhu D, Chen X. Development and clinical verification of a loop-mediated isothermal amplification method for detection of Salmonella species in suspect infected ducks. Poult Sci 2012; 91:979-86. [DOI: 10.3382/ps.2011-01992] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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10
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Li X, Yang F, Gao W, Song H, Tian H, Xu B. Application of pyrosequencing for Salmonella enterica rapid identification. J Microbiol Methods 2012; 89:49-52. [PMID: 22342525 DOI: 10.1016/j.mimet.2012.01.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 01/27/2012] [Accepted: 01/29/2012] [Indexed: 11/30/2022]
Abstract
Application of pyrosequencing of six Salmonella-specific genes as a rapid Salmonella identification method was tested. Primers for hns, hisJ and hilA had non-specific reactions with non-Salmonella strains. Primers for invA, iroB and fimY had specific PCR products and pyrosequences of Salmonella, suggesting that they were suitable for Salmonella rapid identification.
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Affiliation(s)
- Xiujuan Li
- Microbiology Laboratory, Shijiazhuang Center for Disease Control and Prevention, 3 Likang Street, Shijiazhuang, Hebei, China
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Liu B, Zhang L, Zhu X, Shi C, Chen J, Liu W, He X, Shi X. PCR identification of Salmonella serogroups based on specific targets obtained by comparative genomics. Int J Food Microbiol 2011; 144:511-8. [DOI: 10.1016/j.ijfoodmicro.2010.11.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 11/01/2010] [Accepted: 11/07/2010] [Indexed: 11/28/2022]
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12
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Anderson P, Hume M, Byrd J, Hernandez C, Stevens S, Stringfellow K, Caldwell D. Molecular analysis of Salmonella serotypes at different stages of commercial turkey processing. Poult Sci 2010; 89:2030-7. [DOI: 10.3382/ps.2009-00389] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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13
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Matias B, Pinto P, Cossi M, Silva Jr. A, Vanetti M, Nero L. Evaluation of a polymerase chain reaction protocol for the detection of Salmonella species directly from superficial samples of chicken carcasses and preenrichment broth. Poult Sci 2010; 89:1524-9. [DOI: 10.3382/ps.2009-00368] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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14
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Anderson P, Hume M, Byrd J, Hernandez C, Stevens S, Stringfellow K, Caldwell D. Evaluation of repetitive extragenic palindromic-polymerase chain reaction and denatured gradient gel electrophoresis in identifying Salmonella serotypes isolated from processed turkeys. Poult Sci 2010; 89:1293-300. [DOI: 10.3382/ps.2009-00390] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Ben Salem I, Aouni M, Mzoughi R. Two five-plex PCRs methods for identification of common Salmonella spp. serotypes. ANN MICROBIOL 2010. [DOI: 10.1007/s13213-010-0021-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Delibato E, Volpe G, Romanazzo D, De Medici D, Toti L, Moscone D, Palleschi G. Development and application of an electrochemical plate coupled with immunomagnetic beads (ELIME) array for Salmonella enterica detection in meat samples. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:7200-7204. [PMID: 19639993 DOI: 10.1021/jf901181m] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Salmonella is one of the main organisms causing outbreaks of foodborne illness, and meat is one of the major vehicles of salmonellosis throughout the world. A novel analytical immunosensor array, based on a 96-well electrochemical plate coupled with immunomagnetic beads (ELIME array), is proposed for the detection of Salmonella in meat samples. After an optimization study, using Salmonella enterica serotype Enteritidis as reference antigen, the ability of the method to interact with a large number of Salmonella serovars commonly present in food was evaluated. The assay was then used to analyze samples of pork, chicken, beef, and turkey experimentally inoculated with Salmonella as well as real samples. The results were compared with those from the International Standard of Organization (ISO) culture method. The comparison showed that the ELIME array is able to detect a low number of Salmonella cells (1-10 CFU per 25 g) after only 6 h of incubation in a pre-enrichment broth. The investigation revealed a very good agreement between culture and ELIME array methods for meat samples, reducing the time for performing the analysis and obtaining the results quickly.
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Affiliation(s)
- Elisabetta Delibato
- Dipartimento di Sanita Pubblica Veterinaria e Sicurezza Alimentare, Istituto Superiore di Sanita, Viale Regina Elena 299, Roma, Italy
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Shanmugasundaram M, Radhika M, Murali HS, Batra HV. Detection of Salmonella enterica serovar Typhimurium by selective amplification of fliC, fljB, iroB, invA, rfbJ, STM2755, STM4497 genes by polymerase chain reaction in a monoplex and multiplex format. World J Microbiol Biotechnol 2009. [DOI: 10.1007/s11274-009-0025-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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De Clercq D, Ceustermans A, Heyndrickx M, Coosemans J, Ryckeboer J. A rapid monitoring assay for the detection of Salmonella spp. and Salmonella Senftenberg strain W775 in composts. J Appl Microbiol 2007; 103:2102-12. [DOI: 10.1111/j.1365-2672.2007.03449.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Josefsen MH, Krause M, Hansen F, Hoorfar J. Optimization of a 12-hour TaqMan PCR-based method for detection of Salmonella bacteria in meat. Appl Environ Microbiol 2007; 73:3040-8. [PMID: 17351094 PMCID: PMC1892850 DOI: 10.1128/aem.02823-06] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We developed a 12-h Salmonella detection method, based on 8 h of preenrichment, followed by automated DNA extraction and a sensitive real-time PCR. The method was optimized to obtain the highest possible yield of cells and DNA. The growth of different Salmonella strains in various preenrichment media and the effects of adding growth-promoting and selective reagents were explored, taking into account their PCR compatibility. The effects of (i) analyzing larger volumes (1 to 5 ml) from preenriched samples and introducing wash steps prior to DNA extraction, (ii) regulating the amount of paramagnetic particles (increasing it from 60 to 90 microl) in the DNA extraction, (iii) eluting the DNA in reduced volumes (25 or 50 microl rather than 100 microl), and (iv) increasing the PCR template volume (from 5 to 20 microl) were investigated. After 8 h of preenrichment, buffered peptone water yielded the highest number of salmonellae. When analyzing minced meat samples, positive effects of increasing the initial sampling volume from 1 to 5 ml and increasing the amount of paramagnetic particles to 90 microl were observed. However, washing the pellet and eluting the DNA in reduced volumes (25 and 50 microl) had no positive effects and resulted in decreased reproducibility. Increasing the amount of PCR template DNA from 5 to 20 mul improved the threshold cycle value by approximately 2. The improved 12-h PCR method was successfully compared to a reference culture method with 100 minced meat and poultry samples, with a relative accuracy of 99%, a relative sensitivity of 98%, and a relative specificity of 100%.
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Affiliation(s)
- M H Josefsen
- National Food Institute, Bülowsvej 27, DK-1790 Copenhagen, Denmark
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Kumar S, Balakrishna K, Batra HV. Detection of Salmonella enterica serovar Typhi (S. Typhi) by selective amplification of invA, viaB, fliC-d and prt genes by polymerase chain reaction in mutiplex format. Lett Appl Microbiol 2006; 42:149-54. [PMID: 16441380 DOI: 10.1111/j.1472-765x.2005.01813.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS Development of a PCR assay that can target multiple genes for rapid detection of Salmonella enterica serovar Typhi (S. Typhi) from water and food samples. METHODS AND RESULTS PCR primers for invasion, O, H and Vi antigen genes, invA, prt, fliC-d and viaB were designed and used for the rapid detection of S. Typhi by multiplex PCR. Internal amplification control, which co-amplified with prt primers, was also included in the assay. The results showed that all cultures of Salmonella were accurately identified by the assay with no nonspecific amplification in other cultures. The assay had 100% detection probability when a cell suspension of 10(4) CFU ml(-1) (500 CFU per reaction) was used. Salmonella Typhi bacteria were artificially inoculated in the water and food (milk and meat rinse) samples and detected by mPCR after overnight pre-enrichment in buffered peptone water. No Salmonella bacteria could be detected from water samples collected from the field by mPCR or standard culture method. CONCLUSIONS The developed mPCR assay provides specific detection of S. Typhi. SIGNIFICANCE AND IMPACT OF THE STUDY Rapid methods for detection of S. Typhi from complex environmental matrices are almost nonexistent. The mPCR assay reported in this study can be useful to identify S. Typhi bacteria in field environmental samples.
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Affiliation(s)
- S Kumar
- Division of Microbiology, Defence R and D Establishment, Gwalior, Madhya Pradesh, India.
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Mayoral MB, Martín R, Sanz A, Hernández PE, González I, García T. Detection of Kluyveromyces marxianus and other spoilage yeasts in yoghurt using a PCR-culture technique. Int J Food Microbiol 2005; 105:27-34. [PMID: 16026876 DOI: 10.1016/j.ijfoodmicro.2005.06.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2005] [Revised: 05/26/2005] [Accepted: 06/09/2005] [Indexed: 11/30/2022]
Abstract
A combined PCR-culture technique was developed for the detection of viable yeasts in yoghurt samples. Yoghurt samples were inoculated with either viable or heat-inactivated Kluyveromyces marxianus cells, and analyzed before and after incubation for 24 h at 25 degrees C under agitation. DNA was extracted from the samples and amplified using yeast-specific primers targeted at the gene coding for the 18S rRNA. A 251-bp fragment was amplified by the Polymerase Chain Reaction from the yoghurt samples containing initial yeasts counts of 10 cfu g(-1) or higher, whereas no PCR product was generated from control uninoculated yoghurt samples. Comparison of PCR results obtained before and after the incubation step was used to assess yeast viability. Viability was also confirmed by plating on Sabouraud-Dextrose-Chloramphenicol Agar. Moreover, comparison of the results obtained using PCR-culture and plate count methods for the analysis of commercial yoghurt samples, demonstrated that the PCR-culture technique developed in this work can be very useful for the rapid detection of viable spoilage yeasts in dairy industries.
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Affiliation(s)
- María Belén Mayoral
- Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, Spain
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Ahn S, Walt DR. Detection ofSalmonellaspp. Using Microsphere-Based, Fiber-Optic DNA Microarrays. Anal Chem 2005; 77:5041-7. [PMID: 16053320 DOI: 10.1021/ac0505270] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Salmonella spp. are one of the most problematic food pathogens in public health, as they are responsible for food poisoning associated with contamination of meat, poultry, and eggs. Thus, rapid and sensitive detection of Salmonella spp. is required to ensure food safety. In this study, a fiber-optic DNA microarray using microsphere-immobilized oligonucleotide probes specific for the Salmonella invA and spvB genes was developed for detection of Salmonella spp. Microarrays were prepared by randomly distributing DNA probe-functionalized microspheres (3.1-microm diameter) into microwells created by etching optical fiber bundles. Hybridization of the probe-functionalized microspheres to target DNA from Salmonella was performed and visualized using Cy3-labeled secondary probes in a sandwich-type assay format. In this study, 10(3)-10(4) cfu/mL of the target organism could be detected after 1-h hybridization without any additional amplification. The DNA microarray showed no cross-reactivity with other common food pathogens, including E. coli and Y. enterocolitica, and could even detect Salmonella spp. from cocktails of bacterial strains with only moderate loss of sensitivity due to nonspecific binding. This work suggests that fiber-optic DNA microarrays can be used for rapid and sensitive detection of Salmonella spp. Since fiber-optic microarrays can be prepared with different probes, this approach could also enable the simultaneous detection of multiple food pathogens.
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Affiliation(s)
- Soohyoun Ahn
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA
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Affiliation(s)
- Michael Tilley
- USDA-ARS Grain Marketing and Production Research Center, 1515 College Avenue, Manhattan, KS. E-mail: Mention of firm names or trade products does not constitute endorsement by the U.S. Department of Agriculture over others not mentioned. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of name by the USDA implies no approval of the product to the exclusion of others that may also be
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