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Arce C, Cahya-Mawarda P, Arroyo-Manzanares N, Garrido JJ, Arce L. CE method for analyzing Salmonella typhimurium in water samples. J Sep Sci 2017; 41:534-539. [PMID: 29087615 DOI: 10.1002/jssc.201700705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/19/2017] [Accepted: 10/22/2017] [Indexed: 01/10/2023]
Abstract
Salmonella typhimurium is commonly described as a food-borne pathogen. However, natural and drinking water are known to be important sources for the transmission of this pathogen in developing and developed countries. The standard method to determine Salmonella is laborious and many false positives are detected. To solve this, the present work was focused on the development of a capillary zone electrophoresis method coupled to ultraviolet detection for determination of Salmonella typhimurium in water (mineral and tap water). Separations were performed in less than 11 minutes using 4.5 mM Tris (hydroxymethyl)-aminomethane, 4.5 mM boric acid and 0.1 mM ethylene diamine tetraacetate (pH 8.4) with 0.1% v/v poly ethylene oxide as separation buffer. The precision of the method was evaluated in terms of repeatability obtaining a relative standard deviation of 10.5%. Using the proposed method Salmonella typhimurium could be separated from other bacteria that could be present in water such as Escherichia coli. Finally, the proposed methodology was applied to determine Salmonella typhimurium in tap and mineral water.
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Affiliation(s)
- Cristina Arce
- Department of Animal Production, University of Córdoba, Campus of Rabanales, Córdoba, Spain
| | - Panji Cahya-Mawarda
- Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Annex Building, Campus of Rabanales, Córdoba, Spain.,Research Unit for Clean Technology, Indonesian Institute of Sciences, Jalan Cisitu/Sangkuriang, Bandung, Indonesia
| | - Natalia Arroyo-Manzanares
- Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Annex Building, Campus of Rabanales, Córdoba, Spain
| | - Juan J Garrido
- Department of Genetic, University of Córdoba, Campus of Rabanales, Córdoba, Spain
| | - Lourdes Arce
- Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Annex Building, Campus of Rabanales, Córdoba, Spain
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Deekshit VK, Kumar BK, Rai P, Karunasagar I, Karunasagar I. Differential expression of virulence genes and role of gyrA mutations in quinolone resistant and susceptible strains of Salmonella Weltevreden and Newport isolated from seafood. J Appl Microbiol 2016; 119:970-80. [PMID: 26249136 DOI: 10.1111/jam.12924] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/13/2015] [Accepted: 06/27/2015] [Indexed: 11/30/2022]
Abstract
AIMS To investigate the differential expression of virulence genes and role of gyrA mutations in quinolone resistant and susceptible strains of Salmonella isolated from seafood. METHODS AND RESULTS Forty Salmonella isolates from seafood were tested for antibiotic sensitivity. Minimal inhibitory concentration (MIC) was determined and two nalidixic acid-resistant isolates, viz Salmonella Weltevreden (SW9) and Salmonella Newport (SN36) were selected for identifying the mechanism of resistance. SW9 showed mutation in the gyrA gene at codon 83 (Ser to Tyr) while SN36 presented at codon 87 (Asp to Asn). Experimental induction of resistance to a sensitive Salm. Newport (SN71) showed point mutation at codon 87 (Asp to Gly) in the gyrA gene, and was designated SN71R. All the isolates resistant to nalidixic acid had a single mutation at different positions in the gyrA gene. However, induction of resistance to a sensitive Salm. Weltevreden (SW30) was exceptional in that it did not show any mutation in the gyrA region. Use of Phe-Arg-β-naphthylamide (PAβN) also could not reduce MIC below the Clinical and Laboratory Standards Institute guidelines revealing the absence of efflux mediated resistance. Thus, the resistance mechanism in SW30R is unknown. The growth rate of quinolone resistant isolates was slower than the susceptible ones. The resistant isolates showed decreased epithelial cell invasion and intracellular replication. The mRNA expression levels of some of the genes were significantly (P < 0·005) reduced in SN71R compared to the sensitive strain (SN71). CONCLUSIONS Nalidixic acid-resistant Salmonella strains are associated with lower virulence and pathogenicity than the sensitive strains. SIGNIFICANCE AND IMPACT OF THE STUDY This study provided valuable information on the difference in the growth, cytotoxicity, infectivity and expression of virulence genes in resistant and susceptible strains. Furthermore, the gyrA mutation was shown to be the main mechanism of quinolone resistance in Salmonella other than the overexpression of efflux pumps or the presence of plasmid mediated quinolone resistance genes.
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Affiliation(s)
- V K Deekshit
- Department of Biomedical Sciences, Nitte University Center for Science Education and Research, UNESCO MIRCEN for Marine Biotechnology, University Enclave, Mangalore-575018, India
| | - B K Kumar
- Department of Biomedical Sciences, Nitte University Center for Science Education and Research, UNESCO MIRCEN for Marine Biotechnology, University Enclave, Mangalore-575018, India
| | - P Rai
- Department of Biomedical Sciences, Nitte University Center for Science Education and Research, UNESCO MIRCEN for Marine Biotechnology, University Enclave, Mangalore-575018, India
| | - I Karunasagar
- Department of Biomedical Sciences, Nitte University Center for Science Education and Research, UNESCO MIRCEN for Marine Biotechnology, University Enclave, Mangalore-575018, India
| | - I Karunasagar
- Department of Biomedical Sciences, Nitte University Center for Science Education and Research, UNESCO MIRCEN for Marine Biotechnology, University Enclave, Mangalore-575018, India
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Review of Salmonella detection and identification methods: Aspects of rapid emergency response and food safety. Food Control 2015. [DOI: 10.1016/j.foodcont.2014.07.011] [Citation(s) in RCA: 195] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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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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Arnandis-Chover T, Morais S, Tortajada-Genaro LA, Puchades R, Maquieira Á, Berganza J, Olabarria G. Detection of food-borne pathogens with DNA arrays on disk. Talanta 2012; 101:405-12. [PMID: 23158341 DOI: 10.1016/j.talanta.2012.09.049] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 09/10/2012] [Accepted: 09/22/2012] [Indexed: 11/29/2022]
Abstract
A DNA oligonucleotide array for duplex pathogen detection on a DVD platform is developed. The assay involves hybridization of PCR products and optical detection using compact disc technology. Different DNA array constructions for attachment of synthetic oligonucleotides on to DVD surface are evaluated, finding that streptavidin-biotin coupling method yielded the highest sensitivity in combination with enzymatic signal amplification. Issues of importance for the DNA array construction such immobilized probes design, PCR product labeling strategy and composition of the hybridization buffer were addressed. The methodology was proved scoring single nucleotide polymorphisms with high selectivity. The assay capability was also demonstrated by the identification of two pathogenic microorganisms in powder milk samples. In fifty minutes, the DVD-array system identifies Salmonella spp. and Cronobacter spp. (previously named Enterobacter sakazakii) precise and simultaneously with a sensitivity of 10(0) and 10(2) cfu/mL, respectively, in infant milk. Results were in good agreement with those obtained by quantitative real-time PCR.
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Affiliation(s)
- T Arnandis-Chover
- Centro de Reconocimiento Molecular y Desarrollo Tecnológico, Departamento de Química, Universitat Politécnica de Valéncia, Camino de Vera s/n, 46071 Valencia, Spain
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Gangwar M, Waters AM, Bej GA, Bej AK, Mojib N. Detection of Salmonella in Shellfish Using SYBR Green™ I-Based Real-Time Multiplexed PCR Assay Targeting invA and spvB. FOOD ANAL METHOD 2012. [DOI: 10.1007/s12161-012-9503-6] [Citation(s) in RCA: 3] [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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7
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Verdoy D, Barrenetxea Z, Berganzo J, Agirregabiria M, Ruano-López JM, Marimón JM, Olabarría G. A novel Real Time micro PCR based Point-of-Care device for Salmonella detection in human clinical samples. Biosens Bioelectron 2012; 32:259-65. [DOI: 10.1016/j.bios.2011.12.032] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 12/06/2011] [Accepted: 12/16/2011] [Indexed: 11/16/2022]
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8
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Jeyasekaran G, Raj KT, Shakila RJ, Thangarani AJ, Sukumar DR. Detection of Salmonella enterica serovars in shrimps in eight hours by multiplex PCR assay. ANN MICROBIOL 2011. [DOI: 10.1007/s13213-011-0250-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Bhowmick PP, Devegowda D, Ruwandeepika HAD, Karunasagar I, Karunasagar I. Presence of Salmonella pathogenicity island 2 genes in seafood-associated Salmonella serovars and the role of the sseC gene in survival of Salmonella enterica serovar Weltevreden in epithelial cells. Microbiology (Reading) 2011; 157:160-168. [DOI: 10.1099/mic.0.043596-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The type III secretion system encoded by the Salmonella pathogenicity island 2 (SPI-2) has a central role in the pathogenesis of systemic infections by Salmonella. Sixteen genes (ssaU, ssaB, ssaR, ssaQ, ssaO, ssaS, ssaP, ssaT, sscB, sseF, sseG, sseE, sseD, sseC, ssaD and sscA) of SPI-2 were targeted for PCR amplification in 57 seafood-associated serovars of Salmonella. The sseC gene of SPI-2 was found to be absent in two isolates of Salmonella enterica serovar Weltevreden, SW13 and SW39. Absence of sseC was confirmed by sequencing using flanking primers. SW13 had only 66 bp sequence of the sseC gene and SW39 had 58 bp sequence of this gene. A clinical isolate, S. Weltevreden – SW3, 10 : r : z6 – was used to construct a deletion mutant for the sseC gene. Significant reduction in the survival of SW3, 10 : r : z6 ΔsseC and natural mutants SW13 and SW39 in HeLa cells suggests that sseC has a crucial role in the intracellular survival of S. Weltevreden. Expression of sseC was upregulated during the intracellular phase of both S. enterica serovar Typhimurium and clinical isolate S. Weltevreden SW3, 10 : r : z6, suggesting a crucial role for this gene in the survival of S. Weltevreden inside host cells.
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Affiliation(s)
- Patit P. Bhowmick
- Department of Fishery Microbiology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore 575 002, India
| | - Devananda Devegowda
- Department of Fishery Microbiology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore 575 002, India
| | - H. A. Darshanee Ruwandeepika
- Department of Fishery Microbiology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore 575 002, India
| | - Iddya Karunasagar
- Department of Fishery Microbiology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore 575 002, India
| | - Indrani Karunasagar
- Department of Fishery Microbiology, Karnataka Veterinary, Animal and Fisheries Sciences University, College of Fisheries, Mangalore 575 002, India
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Jeyasekaran G, Raj KT, Shakila RJ, Thangarani AJ, Sukumar D, Jailani VAK. Rapid detection of Salmonella enterica serovars by multiplex PCR. World J Microbiol Biotechnol 2010. [DOI: 10.1007/s11274-010-0538-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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11
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Levin RE. The Use of Molecular Methods for Detecting and DiscriminatingSalmonellaAssociated with Foods — A Review. FOOD BIOTECHNOL 2009. [DOI: 10.1080/08905430903320982] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Viswanathan S, Radecka H, Radecki J. Electrochemical biosensors for food analysis. MONATSHEFTE FUR CHEMIE 2009. [DOI: 10.1007/s00706-009-0143-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Dalgaard P, Mejlholm O, Huss H. Conductance method for quantitative determination ofPhotobacterium phosphoreumin fish products. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1365-2672.1996.tb03282.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Ahmed M, Hossain M, Tamiya E. Electrochemical Biosensors for Medical and Food Applications. ELECTROANAL 2008. [DOI: 10.1002/elan.200704121] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Shabarinath S, Sanath Kumar H, Khushiramani R, Karunasagar I, Karunasagar I. Detection and characterization of Salmonella associated with tropical seafood. Int J Food Microbiol 2007; 114:227-33. [PMID: 17141346 DOI: 10.1016/j.ijfoodmicro.2006.09.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Revised: 07/27/2006] [Accepted: 09/19/2006] [Indexed: 11/15/2022]
Abstract
The prevalence of Salmonella in seafood samples collected from the southwest coast of India was studied by conventional culture and by a DNA based molecular technique, polymerase chain reaction (PCR). While conventional culture techniques detected Salmonella in only 20 out of the 100 samples analyzed, direct enrichment lysate PCR detected 52 as positive for Salmonella. A set of three different PCR primers viz., hns, invA and invE were used. It was observed that hns primer detected Salmonella in a significantly higher number of samples. Fourteen out of nineteen isolates belonged to serovar S. enterica Weltevreden. S. Weltevreden isolates were genotyped yielding 4 different patterns both by RAPD and ERIC-PCR but when combined, the overall results discriminated the isolates of S. Weltevreden into 6 different types. This suggests that genetically diverse Salmonella Weltevreden are prevalent in seafood.
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Affiliation(s)
- S Shabarinath
- Department of Fishery Microbiology, Karnataka Veterinary, Animal and Fisheries Sciences, University, College of Fisheries, Mangalore-575 002, India
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Maciorowski KG, Pillai SD, Jones FT, Ricke SC. Polymerase chain reaction detection of foodborne Salmonella spp. in animal feeds. Crit Rev Microbiol 2005; 31:45-53. [PMID: 15839404 DOI: 10.1080/10408410590912970] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Foodborne salmonellosis continues to be a public health issue of considerable concern. Animal feed has been a major link in pre-harvest food animal production. Although monitoring systems and control measures are available to limit Salmonella spp. contamination on animal feeds detection methodology is relatively time consuming in the context of time inputs for feed processing and mixing. Current cultural methods of Salmonella spp. detection in feeds require several days for confirmation. This amount of time represents significant problems if control measures are to be effectively implemented in a fashion that keeps feed processing costs low. Molecular methods offer improved sensitivity and potential reduction in assay time. In particular, several commercial polymerase chain reaction (PCR) assays, and combined PCR-hybridization assays have been suggested as possible means to implement more rapid detection of Salmonella spp. extracted from animal feeds. It has now become possible to rapidly detect and confirm the presence of foodborne Salmonella spp. in feed matrices by commercial amplification detection systems. The primary challenges remaining are to develop more reliable recovery and extraction procedures for routine processing of samples from a wide variety of feed matrices and apply molecular techniques for assessing physiological status of Salmonella spp. contaminants in animal feeds.
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Affiliation(s)
- K G Maciorowski
- Department of Agriculture and Natural Resources, Delaware State University, Dover, Delaware, USA
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Naravaneni R, Jamil K. Rapid detection of food-borne pathogens by using molecular techniques. J Med Microbiol 2005; 54:51-54. [PMID: 15591255 DOI: 10.1099/jmm.0.45687-0] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Traditional methods of identification of food-borne pathogens, which cause disease in humans, are time-consuming and laborious, so there is a need for the development of innovative methods for the rapid identification of food-borne pathogens. Recent advances in molecular cloning and recombinant DNA techniques have revolutionized the detection of pathogens in foods. In this study the development of a PCR-based technique for the rapid identification of the food-borne pathogens Salmonella and Escherichia coli was undertaken. Suitable primers were designed based on specific gene fimA of Salmonella and gene afa of pathogenic E. coli for amplification. Agarose gel electrophoresis and subsequent staining with ethidium bromide were used for the identification of PCR products. The size of the amplified product was 120 bp as shown by comparison with marker DNA. These studies have established that fimA and afa primers were specific for detecting Salmonella and pathogenic E. coli, respectively, in the environmental samples. Thus a rapid, sensitive and reliable technique for the detection of Salmonella and pathogenic E. coli was developed.
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Affiliation(s)
- Rambabu Naravaneni
- Department of Genetics, Bhagwan Mahavir Hospital and Research Centre, Masab tank, Hyderabad, Andhra Pradesh, India-500 004
| | - Kaiser Jamil
- Department of Genetics, Bhagwan Mahavir Hospital and Research Centre, Masab tank, Hyderabad, Andhra Pradesh, India-500 004
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Sanath Kumar H, Sunil R, Venugopal MN, Karunasagar I, Karunasagar I. Detection of Salmonella spp. in tropical seafood by polymerase chain reaction. Int J Food Microbiol 2003; 88:91-5. [PMID: 14527790 DOI: 10.1016/s0168-1605(03)00144-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The incidence of Salmonella spp. in tropical seafood was studied using standard microbiological techniques and polymerase chain reaction (PCR). Six of 20 finfish (30%), 4 of 20 clams (20%) and 1 of 20 shrimp (5%) were positive by culture techniques and by PCR. In a comparative study of different selective enrichment broths and selective plating media, more than one enrichment broth and selective agar were found to be necessary for efficient detection of Salmonella from seafood. Selenite cystine broth (SCB) was found to be more efficient compared to tetrathionate broth (TTB) while both bismuth sulfite agar (BSA) and hektoen enteric agar (HEA) were equally effective as selective plating media for fish. In the case of clams, HEA was found to be more effective. The presence of Salmonella spp. could be detected by PCR amplification of DNA extracted directly from the enrichment broths. In two cases, enrichment broths that were positive by PCR did not yield Salmonella by conventional methods.
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Affiliation(s)
- H Sanath Kumar
- Department of Fishery Microbiology, University of Agricultural Sciences, College of Fisheries, Mangalore-575 002, India
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Lee CY, Panicker G, Bej AK. Detection of pathogenic bacteria in shellfish using multiplex PCR followed by CovaLink NH microwell plate sandwich hybridization. J Microbiol Methods 2003; 53:199-209. [PMID: 12654491 DOI: 10.1016/s0167-7012(03)00032-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Outbreak of diseases associated with consumption of raw shellfish especially oysters is a major concern to the seafood industry and public health agencies. A multiplex PCR amplification of targeted gene segments followed by DNA-DNA sandwich hybridization was optimized to detect the etiologic agents. First, a multiplex PCR amplification of hns, spvB, vvh, ctx and tl was developed enabling simultaneous detection of total Salmonella enterica serotype Typhimurium, Vibrio vulnificus, Vibrio cholerae and Vibrio parahaemolyticus from both pure cultures and seeded oysters. Amplicons were then subjected to a colorimetric CovaLink NH microwell plate sandwich hybridization using phosphorylated and biotinlylated oligonucleotide probes, the nucleotide sequences of which were located internal to the amplified DNA. The results from the hybridization with the multiplexed PCR amplified DNA exhibited a high signal/noise ratio ranging between 14.1 and 43.2 measured at 405 nm wavelength. The sensitivity of detection for each pathogen was 10(2) cells/g of oyster tissue homogenate. The results from this study showed that the combination of the multiplex PCR with a colorimetric microwell plate sandwich hybridization assay permits a specific, sensitive, and reproducible system for the detection of the microbial pathogens in shellfish, thereby improving the microbiological safety of shellfish to consumers.
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Affiliation(s)
- Chi-Ying Lee
- Department of Biology, University of Alabama at Birmingham, 1300 University Boulevard, Birmingham, AL 35294-1170, USA
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Kim SH, An H, Wei CI, Visessanguan W, Benjakul S, Morrissey M, Su YC, Pitta T. Molecular Detection of a Histamine Former, Morganella morganii, in Albacore, Mackerel, Sardine, and a Processing Plant. J Food Sci 2003. [DOI: 10.1111/j.1365-2621.2003.tb05693.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Agarwal A, Makker A, Goel SK. Application of the PCR technique for a rapid, specific and sensitive detection of Salmonella spp. in foods. Mol Cell Probes 2002; 16:243-50. [PMID: 12270264 DOI: 10.1006/mcpr.2002.0418] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We report here the use of a PCR based assay modified by us for the detection of Salmonella spp. in foods, based on amplification of a 236 bp Salmonella specific hin/H2 region [Way et al. (1993) Applied and Environmental Microbiology 59, 1473-1479], using Ampli Taq Gold polymerase. Using this assay we were able to detect all the Salmonella serovars tested. The limit of detection was 1 fg of purified target DNA or N x 10(0) (1-3 cells) cfu ml(-1) of pure bacterial culture. This assay could detect N x 10(0) cfu Salmonella cells g(-1) of the food sample unambiguously in presence of endogenous microflora following 6 h enrichment, thus requires a duration of approximately 10 h for the full processing from DNA template preparation, PCR and visualization of DNA product on agarose gel. The main advantage of this PCR detection method is its sensitivity, and specificity. We also tried to adopt DNA template isolation method simply by boiling the bacterial cells thereby reducing the possibility of contamination, cutting the processing time and cost considerably. This can be an added advantage for the use of this system in simple lab setups.
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Affiliation(s)
- A Agarwal
- Industrial Toxicology Research Centre, PO Box 80, MG Marg, Lucknow-226 001, India
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Hsih HY, Tsen HY. Combination of immunomagnetic separation and polymerase chain reaction for the simultaneous detection of Listeria monocytogenes and Salmonella spp. in food samples. J Food Prot 2001; 64:1744-50. [PMID: 11726153 DOI: 10.4315/0362-028x-64.11.1744] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A method that combined the immunomagnetic separation (IMS) technique and the multiplex polymerase chain reaction (PCR) method (i.e., the IMS-mPCR method) was developed for simultaneous detection of Listreria monocytogenes and Salmonella spp. in food samples. When only the multiplex PCR method was used, it was found that if cell numbers of each of the two target organisms (L. monocytogenes and Salmonella spp.) were above the detection limit, but differed by more than 2 logs-e.g., n x 10(7) to n x 10(4) or n x 10(6) to n x 10(3)--the organism presenting the lower numbers might go undetected. Following the enrichment step with universal preenrichment (UP) broth, if an IMS method using equal quantities of anti-Listeria and anti-Salmonella immunomagnetic beads was performed prior to PCR, both pathogens could be detected unambiguously. Such results could be obtained for target organisms in food samples, such as milk, dairy, and meat products, if similar enrichment and IMS steps were performed prior to PCR.
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Affiliation(s)
- H Y Hsih
- Department of Food Nutrition, Ching-Hwa College of Medical Technology, Tainan, Taiwan, ROC
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Fernández A, García T, Asensio L, Rodríguez MA, González I, Céspedes A, Hernández PE, Martín R. Identification of the clam species Ruditapes decussatus (Grooved carpet shell), Venerupis pullastra (Pullet carpet shell), and Ruditapes philippinarum (Japanese carpet shell)by PCR-RFLP. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2000; 48:3336-3341. [PMID: 10956112 DOI: 10.1021/jf0002185] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
PCR-RFLP analysis has been applied to the identification of three clam species: Ruditapes decussatus (grooved carpet shell), Venerupis pullastra (pullet carpet shell), and Ruditapes philippinarum (Japanese carpet shell). PCR amplification was carried out using a set of primers designed from the DNA nucleotide sequences reported for alpha-actins from humans and various animals. Restriction endonuclease analysis based on sequence data of the PCR products of each clam species revealed the presence of species-specific polymorphic sites for MaeIII and RsaI endonucleases. Electrophoretic analysis of the amplicons digested with MaeIII and RsaI produced species-specific profiles that allowed the genetic identification of the three clam species.
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Affiliation(s)
- A Fernández
- Departamento de Nutrición y Bromatología III, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain
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Chen W, Martinez G, Mulchandani A. Molecular beacons: a real-time polymerase chain reaction assay for detecting Salmonella. Anal Biochem 2000; 280:166-72. [PMID: 10805535 DOI: 10.1006/abio.2000.4518] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Molecular beacons are oligonucleotide probes that become fluorescent upon hybridization. We developed a real-time PCR assay to detect the presence of Salmonella species using these fluorogenic reporter molecules. A 122-base-pair section of the himA was used as the amplification target. Molecular beacons were designed to recognize a 16-base-pair region on the amplicon. As few as 2 colony-forming unit (CFU) per PCR reaction could be detected. We also demonstrated the ability of the molecular beacons to discriminate between amplicons obtained from similar species such as Escherichia coli and Citrobacter freundii in real-time PCR assays. These assays could be carried out entirely in sealed PCR tubes, enabling fast and direct detection of Salmonella in a semiautomated format.
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Affiliation(s)
- W Chen
- Department of Chemical and Environmental Engineering, University of California, Riverside 92521, USA.
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26
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Ivnitski D, Abdel-Hamid I, Atanasov P, Wilkins E, Stricker S. Application of Electrochemical Biosensors for Detection of Food Pathogenic Bacteria. ELECTROANAL 2000. [DOI: 10.1002/(sici)1521-4109(20000301)12:5<317::aid-elan317>3.0.co;2-a] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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27
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Ivnitski D, Abdel-Hamid I, Atanasov P, Wilkins E. Biosensors for detection of pathogenic bacteria. Biosens Bioelectron 1999. [DOI: 10.1016/s0956-5663(99)00039-1] [Citation(s) in RCA: 420] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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28
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Waage AS, Vardund T, Lund V, Kapperud G. Detection of low numbers of Salmonella in environmental water, sewage and food samples by a nested polymerase chain reaction assay. J Appl Microbiol 1999; 87:418-28. [PMID: 10540245 DOI: 10.1046/j.1365-2672.1999.00835.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A polymerase chain reaction (PCR) assay with two nested pairs of primers selected from conserved sequences within a 2.3 kb randomly cloned DNA fragment from the Salmonella typhimurium chromosome was developed. The nested PCR assay correctly identified 128 of a total of 129 Salmonella strains belonging to subspecies I, II, IIIb and IV. One strain of Salm. arizona (ssp. IIIa) tested negative. No PCR products were obtained from any of the 31 non-Salmonella strains examined. The sensitivity of the assay was 2 cfu, as determined by analysis of proteinase K-treated boiled lysates of Salm. typhimurium. The performance of the assay was evaluated for environmental water, sewage and food samples spiked with Salm. typhimurium. Water and sewage samples were filtered and filters were enriched overnight in a non-selective medium. Prior to PCR, the broth cultures were subjected to a rapid and simple preparation procedure consisting of centrifugation, proteinase K treatment and boiling. This assay enabled detection of 10 cfu 100 ml(-1) water with background levels of up to 8700 heterotrophic organisms ml(-1) and 10000 cfu of coliform organisms 100 ml(-1) water. Spiked food samples were analysed with and without overnight enrichment in a non-selective medium using the same assay as above. Nested PCR performed on enriched broths enabled detection of <10 cfu g(-1) food. Variable results were obtained for food samples examined without prior enrichment and most results were negative. This rapid and simple assay provides a sensitive and specific means of screening drinking water or environmental water samples, as well as food samples, for the presence of Salmonella spp.
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Affiliation(s)
- A S Waage
- Department of Bacteriology, National Institute of Public Health, Norwegian College of Veterinary Medicine, Oslo, Norway.
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29
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Detection of Salmonella in food over 30 h using enrichment and polymerase chain reaction. Food Microbiol 1999. [DOI: 10.1006/fmic.1998.0247] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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30
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A rapid PCR-based hybridization assay for the detection of Listeria monocytogenes in channel catfish. Food Microbiol 1999. [DOI: 10.1006/fmic.1998.0237] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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31
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Burtscher C, Fall PA, Wilderer PA, Wuertz S. Detection of Salmonella spp. and Listeria monocytogenes in suspended organic waste by nucleic acid extraction and PCR. Appl Environ Microbiol 1999; 65:2235-7. [PMID: 10224026 PMCID: PMC91323 DOI: 10.1128/aem.65.5.2235-2237.1999] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A nucleic acid-based method for the detection of the bacterial pathogens Salmonella spp. and Listeria monocytogenes in biological waste was developed. The detection limits were less than 10 cells per ml of biological waste. The method does not include a phenol extraction step and can be easily performed in 1 to 2 days.
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Affiliation(s)
- C Burtscher
- Institute of Water Quality Control and Waste Management, Technical University of Munich, Am Coulombwall, D-85748 Garching, Germany
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32
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González I, García T, Fernández A, Sanz B, Hernández PE, Martín R. Rapid enumeration of Escherichia coli in oysters by a quantitative PCR-ELISA. J Appl Microbiol 1999; 86:231-6. [PMID: 10063622 DOI: 10.1046/j.1365-2672.1999.00659.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Direct enumeration of Escherichia coli from oysters was achieved using a polymerase chain reaction (PCR) amplification of the lamB gene coupled with an enzyme-linked immunosorbent assay (ELISA). Amplified PCR products generated using a digoxigenin-labelled primer were heat denatured before being quantified by an ELISA. A biotinylated probe immobilized onto streptavidin-coated microplates was used to capture the digoxigenin-labelled fragments that were detected with a peroxidase antidigoxigenin conjugate. Subsequent enzymic conversion of substrate gave distinct absorbance differences when assaying oyster samples containing E. coli in the range 10-10(5) cfu g-1.
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Affiliation(s)
- I González
- Departamento de Nutrición y Bromatologia III, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
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33
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TU SI, UKNALIS J, PATTERSON D, GEHRING A. DETECTION OF IMMUNOMAGNETICALLY CAPTURED, 4',6-DIAMIDINO-2-PHENYLINDOLE (DAPI)-LABELED E. COLI O157:H7 BY FLUORESCENT MICROSCOPE IMAGING. ACTA ACUST UNITED AC 1998. [DOI: 10.1111/j.1745-4581.1998.tb00207.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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34
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Vickery MC, Smith AL, DePaola A, Jones DD, Steffan RJ, Bej AK. Optimization of the arbitrarily-primed polymerase chain reaction (AP-PCR) for intra-species differentiation of Vibrio vulnificus. J Microbiol Methods 1998. [DOI: 10.1016/s0167-7012(98)00056-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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35
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Detection of pathogenic and spoilage micro-organisms in food with the polymerase chain reaction. Food Microbiol 1998. [DOI: 10.1006/fmic.1997.0134] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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36
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Pillai SD. Rapid molecular detection of microbial pathogens: breakthroughs and challenges. ARCHIVES OF VIROLOGY. SUPPLEMENTUM 1997; 13:67-82. [PMID: 9413527 DOI: 10.1007/978-3-7091-6534-8_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Microbiological contamination of foods and drinking water is a global problem, and a significant amount of expense is being incurred as a result of such contamination. The microorganisms associated with almost half of all disease outbreaks still go unidentified, primarily as a result of inadequate monitoring and surveillance. Though significant improvements have been made in refining molecular methods for detecting infectious agents, a majority of these methods are being employed only on clinical samples where pathogen densities are much higher than those found in environmental and food samples. Comparative evaluations of the various protocols in terms of cost, sensitivity, specificity, speed, and reproducibility need to be undertaken so that the true applicability of these methods can determined. In the future, molecular methods, especially gene amplifications and in situ hybridizations, will find increasing applications in the differentiation of viable and non-viable organisms, in predicting antimicrobial resistance, and in the identification and characterization of unculturable microorganisms. Though molecular detection methods will not totally replace conventional methods, they will significantly enhance our ability to detect microbial pathogens rapidly.
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Affiliation(s)
- S D Pillai
- Environmental Science Program, Texas A & M University Research Center, El Paso, USA
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37
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Brewster JD, Gehring AG, Mazenko RS, Van Houten LJ, Crawford CJ. Immunoelectrochemical assays for bacteria: use of epifluorescence microscopy and rapid-scan electrochemical techniques in development of an assay for Salmonella. Anal Chem 1996; 68:4153-9. [PMID: 8946793 DOI: 10.1021/ac9604503] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Immunoelectrochemical sensors in which the sensor surface functions as both analyte capture phase and electrochemical detector have recently been developed for bacteria analysis. The speed and sensitivity of these devices make them very attractive for applications such as the detection of pathogenic microorganisms in food and water. However, the development and optimization of assays utilizing these sensors can be complicated by undesired interactions between the capture and detection functions. Modification of the sensor to achieve improvements in one function can have deleterious effects on the other function, and such effects can be difficult to diagnose and correct. In the course of investigations on immunoelectrochemical detection of Salmonella, we developed a rapid, nondestructive epifluorescence microscopy method to determine bacteria capture efficiency. This method enabled us to study capture and detection functions independently and efficiently identify performance-limiting factors. Rapid-scan electrochemical methods were used to optimize detection sensitivity and to provide diagnostic information on detection performance.
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Affiliation(s)
- J D Brewster
- Eastern Regional Research Center, U.S. Department of Agriculture, Wyndmoor, Pennsylvania 19038, USA
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38
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Cohen HJ, Mechanda SM, Lin W. PCR amplification of the fimA gene sequence of Salmonella typhimurium, a specific method for detection of Salmonella spp. Appl Environ Microbiol 1996; 62:4303-8. [PMID: 8953701 PMCID: PMC168256 DOI: 10.1128/aem.62.12.4303-4308.1996] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The goal of this study was to evaluate the suitability of the fimA gene amplification by PCR as a specific method for detection of Salmonella strains. Salmonella typhimurium and other pathogenic members of the family Enterobacteriaceae produce morphologically and antigenically related, thin, aggregative, type 1 fimbriae. A single gene, fimA, encodes the major fimbrial unit. In order to obtain higher specificity, we have selected a series of primers internal to the fimA gene sequence and have developed a PCR method for detecting Salmonella strains. A collection of 376 strains of Salmonella comprising over 80 serovars, isolated from animals and humans in Canada, have been used to evaluate this PCR method. Forty non-Salmonella strains were also tested by the same procedure. Cultures were screened by inoculating a single colony of bacteria directly into a PCR mixture containing a pair of primers specific for the fimA gene. The specific PCR product is an 85-bp fragment which was visualized by polyacrylamide gel electrophoresis and ethidium bromide staining. All Salmonella strains gave positive results by the PCR. Feed and milk samples contaminated by Salmonella strains were also detected by this procedure. The detection of all Salmonella strains tested and the failure to amplify the fragment from non-Salmonella strains confirm that the fimA gene contains sequences unique to Salmonella strains and demonstrate that this gene is a suitable PCR target for detection of Salmonella strains in food samples.
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Affiliation(s)
- H J Cohen
- Laboratory Services Division, Food Production and Inspection Branch, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada
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39
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Lin CK, Tsen HY. Use of two 16S DNA targeted oligonucleotides as PCR primers for the specific detection of Salmonella in foods. THE JOURNAL OF APPLIED BACTERIOLOGY 1996; 80:659-66. [PMID: 8698667 DOI: 10.1111/j.1365-2672.1996.tb03271.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A 16S DNA targeted polymerase chain reaction (PCR) method specific for the detection of Salmonella isolates with various serotypes was developed. The primers used for such a PCR method were 16SF1 and 16SIII. 16SF1 is the reverse and complementary strand of 16SI which has been shown to be able to hybridize with Salmonella and Citrobacter spp. 16III on the other hand, is able to hybridize with Klebsiella and Serratia spp. in addition to Salmonella. Although 16SF1 and 16SIII were not specific to Salmonella only, when they were used as PCR primers, only the Salmonella isolates could be specifically detected. The interference from Citrobacter, Klebsiella and Serratia spp. could be prevented. None of the other non-Salmonella isolates including strains of the family of Enterobacteriaceae closely related to Salmonella would generate the false-positive reaction. When this PCR system was used for the detection of Salmonella cells artificially contaminated in food samples, results obtained were satisfactory. A detection limit of N x 10(0) cells per assay could be obtained.
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Affiliation(s)
- C K Lin
- Department of Food Science, National Chung-Hsing University, Taichung, Taiwan, ROC
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40
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Coleman SS, Melanson DM, Biosca EG, Oliver JD. Detection of Vibrio vulnificus biotypes 1 and 2 in eels and oysters by PCR amplification. Appl Environ Microbiol 1996; 62:1378-82. [PMID: 8919800 PMCID: PMC167905 DOI: 10.1128/aem.62.4.1378-1382.1996] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
DNA extraction procedures and PCR conditions to detect Vibrio vulnificus cells naturally occurring in oysters were developed. In addition, PCR amplification of V. vulnificus from oysters seeded with biotype 1 cells was demonstrated. By the methods described, V. vulnificus cells on a medium (colistin-polymyxin B-cellobiose agar) selective for this pathogen were detectable in oysters harvested in January and March, containing no culturable cells (< 67 CFU/g), as well as in oysters harvested in May and June, containing culturable cells. It was possible to complete DNA extraction, PCR, and gel electrophoresis within 10 h by using the protocol described for oysters. V. vulnificus biotype 2 cells were also detected in eel tissues that had been infected with this strain and subsequently preserved in formalin. The protocol used for detection of V. vulnificus cells in eels required less than 5 h to complete. Optimum MgCl2 concentrations for the PCR of V. vulnificus from oysters and eels were different, although the same primer pair was used for both. This is the first report on the detection of cells of V. vulnificus naturally present in shellfish and represents a potentially powerful method for monitoring this important human and eel pathogen.
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Affiliation(s)
- S S Coleman
- Department of Biology, University of North Carolina at Charlotte 28223, USA
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41
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Lee CY, Pan SF, Chen CH. Sequence of a cloned pR72H fragment and its use for detection of Vibrio parahaemolyticus in shellfish with the PCR. Appl Environ Microbiol 1995; 61:1311-7. [PMID: 7747952 PMCID: PMC167386 DOI: 10.1128/aem.61.4.1311-1317.1995] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The nucleotide sequence of pR72H cloned from Vibrio parahaemolyticus 93 was determined. We examined all V. parahaemolyticus gene sequences published in the GenBank-EMBL databases for homology and found that no other DNA sequence of V. parahaemolyticus was highly homologous to the sequence reported in this study. A pair of primers, VP33-VP32, derived from a pR72H fragment were selected to detect V. parahaemolyticus. The sensitivity of PCR detection for a pure culture of V. parahaemolyticus was 10 cells from crude bacterial lysates. Furthermore, a detection level of 2.6 fg, equivalent to 1 cell, was obtained by using purified chromosomal DNA as the template. The expected PCR products were obtained from all V. parahaemolyticus strains tested (n = 124), while no PCR amplicons were found in other vibrios or related genera (n = 50). High levels (10(6) to 10(10) CFU/ml) of Escherichia coli cells did not affect the PCR assay sensitivity. The presence of 10(8) V. parahaemolyticus cells or 10(9) E. coli cells in the PCR mixtures completely inhibited the PCR. When oyster samples were inoculated with V. parahaemolyticus 93 and cultured in tryptic soy broth containing 3% NaCl for 3 h at 35 degrees C, an initial sample inoculum level of 9.3 CFU/g was detected in a PCR assay with crude bacterial lysates. The PCR assay with enrichment culturing in salt polymyxin broth was compared with the conventional method for naturally contaminated shellfish and fish samples. We conclude that this PCR assay with enrichment culturing is a good alternative method for the detection of V. parahaemolyticus.
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Affiliation(s)
- C Y Lee
- Graduate Institute of Agricultural Chemistry, National Taiwan University, Taipei, Republic of China
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42
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Abstract
Salmonella is one of the most important foodborne pathogens around the world. The knowledge that very low numbers of Salmonella cells can be infectious emphasizes the need for stringent food safety measures Traditional methods for isolating and identifying Salmonella in food rely on preenrichment, selective enrichment in selective and differential media, biochemical tests, and serological confirmation. Recent advances in diagnostic technology have considerably altered testing methods for foodborne Salmonella. Many commercial assay systems and kits that use newer technologies are available to facilitate the identification of Salmonella in foods. These systems include miniaturized biochemical tests, new media formulations, automated instrumentation, DNA/RNA probes, antibody-dependent assays, and polymerase chain reaction. The technologies used for these systems are described, and the various kit formats are compared. Among the limitations of detection methods in terms of food safety are timeliness, limits of detection, and differentiation of virulent and nonvirulent isolates. Current efforts of prevention measures and strategies at different links of the food chain such as consumer education and hazard analysis and critical control point (HACCP) programs are reviewed, Global approaches to food safety are needed..
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Affiliation(s)
- M Tietjen
- Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-1600, USA
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43
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Pillai SD, Ricke SC. Strategies to accelerate the applicability of gene amplification protocols for pathogen detection in meat and meat products. Crit Rev Microbiol 1995; 21:239-61. [PMID: 8688154 DOI: 10.3109/10408419509113542] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Traditionally, microbiological testing of meat products has involved isolating microorganisms and performing specific biochemical, and in some cases serological, tests to confirm the presence or absence of suspected food-borne pathogens. Given the public attention meat products have received as sources of food-borne disease, there has been considerable interest in the application of rapid detection techniques that require hours rather than days for completion. Theoretically, rapid detection methods could reduce the time from the initial sampling to confirmation so that conclusive results would be available by the time to process the meat product. Both direct gene probe hybridization as well as gene amplification methods show promise as rapid detection techniques. At present, direct gene probe hybridization are being commercially utilized to confirm the presence of a suspected pathogen. A number of gene amplification protocols for detecting food-borne bacterial pathogens have been published. However, many of these studies have utilized spiked samples rather than naturally contaminated samples and many of them have involved extended template extraction/purification methodologies. There is still only a very limited amount of information on the efficacies of the various protocols in detecting bacterial pathogens, especially toxigenic Escherichia coli, Salmonella spp., Campylobacter spp., and Listeria spp., in naturally contaminated food samples. In order to develop gene amplification protocols that have relevance to the meat industry, there must be a concerted effort to utilize naturally contaminated samples in the development and evaluation of protocols, as well as to initiate multilaboratory round robin evaluations of select protocols. Availability of multilaboratory tested methodologies would provide a means to design pathogen detection strategies at the quality control level rather than an end product confirmatory response to an already documented outbreak.
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Affiliation(s)
- S D Pillai
- Environmental Science Program, Texas A&M University Research Center, El Paso 79927, USA
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