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Recent and emerging innovations in Salmonella detection: a food and environmental perspective.

Bell RL, Jarvis KG, Ottesen AR, McFarland MA, Brown EW - Microb Biotechnol (2016)

Bottom Line: Rapid, reliable detection and identification of this pathogen in food and environmental sources is key to safeguarding the food supply.Unfortunately, the time to result is too long to effectively monitor foodstuffs, especially those with very short shelf lives.Advances in traditional microbiology and molecular biology over the past 25 years have greatly improved the speed at which this pathogen is detected.

View Article: PubMed Central - PubMed

Affiliation: Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, MD, USA.

No MeSH data available.


Related in: MedlinePlus

Overview of the U.S. Food and Drug Administration Bacterial Analytical Manual (FDA‐BAM) workflow for the detection, isolation and subtyping of Salmonella (Andrews et al., 2011). Detection and isolation of Salmonella requires 5 days. Subsequent confirmation and subtyping may take up to a week longer. Various, newer molecular methods such as PCR/qPCR, MS, WGS and metagenomics, may shorten the time to result and may be incorporated into the workflow at the indicated steps.
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mbt212359-fig-0001: Overview of the U.S. Food and Drug Administration Bacterial Analytical Manual (FDA‐BAM) workflow for the detection, isolation and subtyping of Salmonella (Andrews et al., 2011). Detection and isolation of Salmonella requires 5 days. Subsequent confirmation and subtyping may take up to a week longer. Various, newer molecular methods such as PCR/qPCR, MS, WGS and metagenomics, may shorten the time to result and may be incorporated into the workflow at the indicated steps.

Mentions: Current testing of food and environmental samples for the presence of Salmonella can be divided into three stages: (i) detection of the pathogen; (ii) identification of the isolate as Salmonella and its specific serovar designation; and (iii) subtyping of the isolate for association with any clinical cases of salmonellosis. Detection methods rely on traditional bacterial culture procedures that employ the use of serial enrichments with increasing selectivity culminating in the isolation of Salmonella on selective‐differential agar plates (Fig. 1) (Andrews et al., 2011; USDA FSIS, 2014). The process takes up to 5 days to gather a presumptive positive isolate. Confirmation relies on traditional biochemical testing of sugar and nutrient utilization media, which can take days to complete. Even with newer automated technologies that permit simultaneous testing of multiple analytes at least 24 h is needed for a confirmation of Salmonella. DNA finger printing techniques, such as pulsed‐field gel electrophoresis (PFGE), ribotyping and intergenic sequence (IGS) ribotyping have all been used to subtype Salmonella isolates. All these techniques are based on a similar idea of examining DNA size differences on an agarose gel. For ribotyping, genomic DNA is digested, separated on an agarose gel and then hybridized to rRNA operons to visualize the banding pattern. After comparison to a database of fingerprints species, serovar and occasionally strain identifications can be made (Bailey et al., 2002). More discriminatory power maybe available with IGS ribotyping, where the size differences found within the intergenic spacer regions between 16S and 23S rRNA regions are examined. Here, the regions are amplified by polymerase chain reaction (PCR) before gel electrophoresis is done. The banding patterns allow for differentiation between strains of Salmonella within a serovar (Brown, 2001). Neither of these techniques has been widely adopted. Federal and State agencies within the United States and many other countries around the world rely on PFGE to subtype Salmonella. For this technique, genomic DNA is digested by the restriction endonuclease XbaI. The DNA fragments are separated on an agarose gel subjected to a pulsed electric field. DNA is visualized by ethidium bromide staining and fingerprints are analysed using specific software available in BioNumberics (Applied Maths) (Ribot et al., 2006). The power of PFGE is the ability to compare the resultant fingerprint patterns to a large national database housed and maintained by the Centers for Disease Control and Prevention (CDC), aka the PulseNet reference library (Swaminathan et al., 2001). The use of PFGE and the implementation of PulseNet have greatly increased the United State's ability of track and trace back illness clusters and outbreaks. Unfortunately, PFGE still requires a pure isolate and a minimum of 3 days to complete (Ribot et al., 2006).


Recent and emerging innovations in Salmonella detection: a food and environmental perspective.

Bell RL, Jarvis KG, Ottesen AR, McFarland MA, Brown EW - Microb Biotechnol (2016)

Overview of the U.S. Food and Drug Administration Bacterial Analytical Manual (FDA‐BAM) workflow for the detection, isolation and subtyping of Salmonella (Andrews et al., 2011). Detection and isolation of Salmonella requires 5 days. Subsequent confirmation and subtyping may take up to a week longer. Various, newer molecular methods such as PCR/qPCR, MS, WGS and metagenomics, may shorten the time to result and may be incorporated into the workflow at the indicated steps.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4835567&req=5

mbt212359-fig-0001: Overview of the U.S. Food and Drug Administration Bacterial Analytical Manual (FDA‐BAM) workflow for the detection, isolation and subtyping of Salmonella (Andrews et al., 2011). Detection and isolation of Salmonella requires 5 days. Subsequent confirmation and subtyping may take up to a week longer. Various, newer molecular methods such as PCR/qPCR, MS, WGS and metagenomics, may shorten the time to result and may be incorporated into the workflow at the indicated steps.
Mentions: Current testing of food and environmental samples for the presence of Salmonella can be divided into three stages: (i) detection of the pathogen; (ii) identification of the isolate as Salmonella and its specific serovar designation; and (iii) subtyping of the isolate for association with any clinical cases of salmonellosis. Detection methods rely on traditional bacterial culture procedures that employ the use of serial enrichments with increasing selectivity culminating in the isolation of Salmonella on selective‐differential agar plates (Fig. 1) (Andrews et al., 2011; USDA FSIS, 2014). The process takes up to 5 days to gather a presumptive positive isolate. Confirmation relies on traditional biochemical testing of sugar and nutrient utilization media, which can take days to complete. Even with newer automated technologies that permit simultaneous testing of multiple analytes at least 24 h is needed for a confirmation of Salmonella. DNA finger printing techniques, such as pulsed‐field gel electrophoresis (PFGE), ribotyping and intergenic sequence (IGS) ribotyping have all been used to subtype Salmonella isolates. All these techniques are based on a similar idea of examining DNA size differences on an agarose gel. For ribotyping, genomic DNA is digested, separated on an agarose gel and then hybridized to rRNA operons to visualize the banding pattern. After comparison to a database of fingerprints species, serovar and occasionally strain identifications can be made (Bailey et al., 2002). More discriminatory power maybe available with IGS ribotyping, where the size differences found within the intergenic spacer regions between 16S and 23S rRNA regions are examined. Here, the regions are amplified by polymerase chain reaction (PCR) before gel electrophoresis is done. The banding patterns allow for differentiation between strains of Salmonella within a serovar (Brown, 2001). Neither of these techniques has been widely adopted. Federal and State agencies within the United States and many other countries around the world rely on PFGE to subtype Salmonella. For this technique, genomic DNA is digested by the restriction endonuclease XbaI. The DNA fragments are separated on an agarose gel subjected to a pulsed electric field. DNA is visualized by ethidium bromide staining and fingerprints are analysed using specific software available in BioNumberics (Applied Maths) (Ribot et al., 2006). The power of PFGE is the ability to compare the resultant fingerprint patterns to a large national database housed and maintained by the Centers for Disease Control and Prevention (CDC), aka the PulseNet reference library (Swaminathan et al., 2001). The use of PFGE and the implementation of PulseNet have greatly increased the United State's ability of track and trace back illness clusters and outbreaks. Unfortunately, PFGE still requires a pure isolate and a minimum of 3 days to complete (Ribot et al., 2006).

Bottom Line: Rapid, reliable detection and identification of this pathogen in food and environmental sources is key to safeguarding the food supply.Unfortunately, the time to result is too long to effectively monitor foodstuffs, especially those with very short shelf lives.Advances in traditional microbiology and molecular biology over the past 25 years have greatly improved the speed at which this pathogen is detected.

View Article: PubMed Central - PubMed

Affiliation: Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, MD, USA.

No MeSH data available.


Related in: MedlinePlus