Detection and Identification of <i>Salmonella</i> Typhimurium in Bovine Diarrhoeic Fecal Samples by Immunomagnetic Separation and Multiplex PCR Assay

Salehi, Taghi Zahraei; Tadjbakhsh, H.; Atashparvar, N.; Nadalian, Mohammad Gholi; Mahzounieh, Mohammadreza

doi:10.1111/j.1863-2378.2007.01061.x

Cited by 24 publications

(4 citation statements)

References 35 publications

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“…For S. Typhimurium, PCR assays were published targeting the O and H1, H2 antigen-encoding genes (Salehi et al 2007;Lim et al 2003;Soumet et al 1999) or other genes predominantly found in the genome of this serovar (Kim et al 2006a). S. Typhimurium-specific real-time PCRbased assays were not found in literature.…”

Section: Pcr-based Serovar-specific Identification Methodsmentioning

confidence: 99%

Polymerase Chain Reaction for the Rapid Detection and Serovar Identification of Salmonella in Food and Feeding Stuff

et al. 2008

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The polymerase chain reaction (PCR) is one of the most important rapid methods for the sensitive and specific detection of pathogenic and spoilage microorganisms. The method is increasingly applied in surveillance and monitoring programs to detect pathogens, especially for ensuring the safety and quality of food. The food-borne pathogen Salmonella together with Campylobacter is the most predominant bacterial pathogen in Europe, causing approximately 160,000 confirmed human cases per year. During the last two decades, the importance of Salmonella for food safety triggered the development of dozens of PCR-based detection methods. They promise significant advantages compared to the traditional culture-based methods with respect to speed, easiness, reliability, sensitivity, cost effectiveness, and automation. However, many of them are not applicable because of lacking validation procedures. Meanwhile, PCR has internationally been standardized and guidelines as well as standards for the validation of alternative methods, such as PCR, were established. This review will give an overview of the historical development of PCR-based methods for the detection of Salmonella including validation aspects and summarizes the state-of-the-art for the detection of Salmonella in food and feeding stuff by realtime PCR. Furthermore, current multiplex PCR-based serovar-specific identification methods will be reviewed.

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Section: Pcr-based Serovar-specific Identification Methodsmentioning

confidence: 99%

Polymerase Chain Reaction for the Rapid Detection and Serovar Identification of Salmonella in Food and Feeding Stuff

et al. 2008

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“…Three to four suspected colonies were chosen and subcultured, and the isolates were confirmed as E coli by conventional biochemical tests. Total genomic DNA was extracted from overnight cultures on Luria Bertani agar (Merck) by the boiling method, as described by Zahraei Salehi and others (2007), and the supernatant was subsequently used as the template in the PCR mixture. All E coli isolates were screened by multiplex PCR using four pairs of specific primers for stx1, stx2, eae and Ehly (Paton and Paton 1998a).…”

Section: Methodsmentioning

confidence: 99%

Virulence gene profiles and intimin subtypes of Shiga toxin‐producingEscherichia coliisolated from healthy and diarrhoeic calves

et al. 2010

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The virulence properties of Shiga toxin-producing Escherichia coli (STEC) strains isolated from diarrhoeic and non-diarrhoeic calves were compared. The strains were also tested for O157:H7, O111 and O26 serotypes, using PCR and conventional serotyping methods. E coli strains isolated from 297 faecal samples, from 200 diarrhoeic and 97 non-diarrhoeic calves, were screened by multiplex PCR assay for the stx1, stx2, eae and Ehly virulence genes. STECs were recovered from 8 per cent of diarrhoeic calves and 10.3 per cent of non-diarrhoeic calves. The predominant virulence gene profile was stx1/eae/Ehly (47.3 per cent) among isolates from diarrhoeic calves and eae/Ehly (36.8 per cent) among isolates from non-diarrhoeic calves. Among three tested serogroups, the predominant serogroup was O26 (18.4 per cent), and O157:H7 was not detected. Intimin subtyping by restriction fragment length polymorphism analysis revealed only three intimin subtypes (β, γ and ). A significant difference was observed in the distribution of Int- between two groups. Int- was present in 50 per cent of the isolates from diarrhoeic calves and in 11.1 per cent of the isolates from non-diarrhoeic calves; this difference was statistically significant (P=0.01).

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“…All effective molecular detection methods (such as PCR based methods and isothermal methods) require target genes. The target genes inv A, ttr RSBCA (operon including 5 genes of ttr R, ttr S, ttr B, ttr C, ttr A), pho P, fim A, agf A, and spv C have been frequently used either separately or in combination for Salmonella detection in many PCR and loop-mediated isothermal amplification (LAMP) assays 8 – 18 . All these target genes are located on chromosome, except for spv C, which is encoded on a plasmid.…”

Section: Introductionmentioning

confidence: 99%

Whole genome sequencing and protein structure analyses of target genes for the detection of Salmonella

Cao

Brown

et al. 2021

Sci Rep

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Rapid and sensitive detection of Salmonella is a critical step in routine food quality control, outbreak investigation, and food recalls. Although various genes have been the targets in the design of rapid molecular detection methods for Salmonella, there is limited information on the diversity of these target genes at the level of DNA sequence and the encoded protein structures. In this study, we investigated the diversity of ten target genes (invA, fimA, phoP, spvC, and agfA; ttrRSBCA operon including 5 genes) commonly used in the detection and identification of Salmonella. To this end, we performed whole genome sequencing of 143 isolates of Salmonella serotypes (Enteritidis, Typhimurium, and Heidelberg) obtained from poultry (eggs and chicken). Phylogenetic analysis showed that Salmonella ser. Typhimurium was more diverse than either Enteritidis or Heidelberg. Forty-five non-synonymous mutations were identified in the target genes from the 143 isolates, with the two most common mutations as T ↔ C (15 times) and A ↔ G (13 times). The gene spvC was primarily present in Salmonella ser. Enteritidis isolates and absent from Heidelberg isolates, whereas ttrR was more conserved (0 non-synonymous mutations) than ttrS, ttrB, ttrC, and ttrA (7, 2, 2, and 7 non-synonymous mutations, respectively). Notably, we found one non-synonymous mutation (fimA-Mut.6) across all Salmonella ser. Enteritidis and Salmonella ser. Heidelberg, C → T (496 nt postion), resulting in the change at AA 166 position, Glutamine (Q) → Stop condon (TAG), suggesting that the fimA gene has questionable sites as a target for detection. Using Phyre2 and SWISS-MODEL software, we predicted the structures of the proteins encoded by some of the target genes, illustrating the positions of these non-synonymous mutations that mainly located on the α-helix and β-sheet which are key elements for maintaining the conformation of proteins. These results will facilitate the development of sensitive molecular detection methods for Salmonella.

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Detection and Identification of Salmonella Typhimurium in Bovine Diarrhoeic Fecal Samples by Immunomagnetic Separation and Multiplex PCR Assay

Cited by 24 publications

References 35 publications

Polymerase Chain Reaction for the Rapid Detection and Serovar Identification of Salmonella in Food and Feeding Stuff

Polymerase Chain Reaction for the Rapid Detection and Serovar Identification of Salmonella in Food and Feeding Stuff

Virulence gene profiles and intimin subtypes of Shiga toxin‐producingEscherichia coliisolated from healthy and diarrhoeic calves

Whole genome sequencing and protein structure analyses of target genes for the detection of Salmonella

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