Development of bioluminescent Salmonella strains for use in food safety

Karsi, Attila; Howe, Kevin; Kirkpatrick, Tasha B; Wills, Robert W.; Bailey, R. H.; Lawrence, Mark L.

doi:10.1186/1471-2180-8-10

Cited by 22 publications

(19 citation statements)

References 38 publications

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“…It is of interest that expression of bioluminescence in S . Schwarzengrund was also the lowest in the plasmid lux system, pAK lux 1, reported previously [19]. These results indicate plasmid pBEN276 can be utilized to construct a stable reporting system within the chromosome of Salmonella enterica serotypes for use in extended in-vitro and in-vivo trials.…”

Section: Resultssupporting

confidence: 62%

Development of stable reporter system cloning luxCDABE genes into chromosome of Salmonella enterica serotypes using Tn7 transposon

et al. 2010

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BackgroundSalmonellosis may be a food safety problem when raw food products are mishandled and not fully cooked. In previous work, we developed bioluminescent Salmonella enterica serotypes using a plasmid-based reporting system that can be used for real-time monitoring of the pathogen's growth on food products in short term studies. In this study, we report the use of a Tn7-based transposon system for subcloning of luxCDABE genes into the chromosome of eleven Salmonella enterica serotypes isolated from the broiler production continuum.ResultsWe found that the lux operon is constitutively expressed from the chromosome post-transposition and the lux cassette is stable without external pressure, i.e. antibiotic selection, for all Salmonella enterica serotypes used. Bioluminescence expression is based on an active electron transport chain and is directly related with metabolic activity. This relationship was quantified by measuring bioluminescence against a temperature gradient in aqueous solution using a luminometer. In addition, bioluminescent monitoring of two serotypes confirmed that our chicken skin model has the potential to be used to evaluate pathogen mitigation strategies.ConclusionsThis study demonstrated that our new stable reporting system eliminates bioluminescence variation due to plasmid instability and provides a reliable real-time experimental system to study application of preventive measures for Salmonella on food products in real-time for both short and long term studies.

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Section: Resultssupporting

confidence: 62%

Development of stable reporter system cloning luxCDABE genes into chromosome of Salmonella enterica serotypes using Tn7 transposon

et al. 2010

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“…By inoculating birds with a bioluminescent Salmonella Typhimurium LT2 isolate and imaging with the In Vivo Imaging System (IVIS ® ; PerkinElmer), we can view colonization in the gastrointestinal tract and investigate various treatment strategies. One advantage of the IVIS is the ability to quantify bioluminescence which is directly related to the levels of the target bacteria present (Karsi et al , 2008 ; Foucault et al , 2009 ). The objective of this study was to evaluate the efficacy of a product containing a combination of MCFA (C6-C12) for reducing early Salmonella colonization in turkey poults.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Medium Chain Fatty Acid Feed Supplementation for ReducingSalmonellaTyphimurium Colonization in Turkey Poults

Evans

Collins

Pierson

et al. 2017

Foodborne Pathogens and Disease

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Studies indicate that persistent Salmonella colonization occurs in poultry that are infected early in life, leading to both food safety and public health concerns. Development of improved preharvest Salmonella management strategies is needed to reduce poultry product contamination. The objective of this study was to evaluate the efficacy of a product containing medium chain fatty acids (MCFA) for reducing early Salmonella colonization in turkey poults. Day-of-hatch turkeys were provided a standard starter diet supplemented with MCFA at 0 (negative and positive controls), 1.5, 3, 4.5, or 6 lbs/ton of feed. Positive control and MCFA treated birds were also crop-gavaged with 108 colony forming units (CFU) of bioluminescent Salmonella Typhimurium. Gastrointestinal tissue samples were collected at 3 days postinoculation for bioluminescence imaging (Meckel's diverticulum to the cloaca) and selective enumeration (cecal contents). Quantification of bioluminescence indicated that the 4.5 and 6 lbs/ton MCFA groups had significantly less colonization than the positive control group (p = 0.0412 and p < 0.0001, respectively). Similarly, significantly lower numbers (1-log10 CFU/g reduction) of Salmonella were observed in the ceca of the 6 lbs/ton MCFA group compared to the positive control group (p = 0.0153). These findings indicate that incorporation of MCFA in turkey diets can significantly reduce early Salmonella colonization. In addition, this study highlights the utility of bioluminescence imaging as a screening methodology for assessing the efficacy of treatments that may reduce Salmonella in poultry.

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“…Bacteria numbers and bioluminescence correlations were very good (r = 0.99) in 12 strains of Salmonella transferred with the pAK1-lux plasmid and for a majority of the strains the minimum detectable bacterial numbers was less than 1500 CFU/ml [12]. The above studies were similar to Experiment 2 results of good correlations for pAK1-lux and pXEN-1 evaluated in the 1 ml black centrifuge tube format as well as the black 96-well plate format (Figure 3 and 4).…”

Section: Resultsmentioning

confidence: 99%

Photonic plasmid stability of transformed Salmonella Typhimurium: A comparison of three unique plasmids

et al. 2009

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BackgroundAcquiring a highly stable photonic plasmid in transformed Salmonella Typhimurium for use in biophotonic studies of bacterial tracking in vivo is critical to experimental paradigm development. The objective of this study was to determine stability of transformed Salmonella Typhimurium (S. typh-lux) using three different plasmids and characterize their respective photonic properties.ResultsIn presence of ampicillin (AMP), S. typh-lux with pCGLS-1, pAK1-lux and pXEN-1 plasmids exhibited 100% photon-emitting colonies over a 10-d study period. Photon emitters of S. typh-lux with pCGLS-1, pAK1-lux and pXEN-1 without AMP selection decreased over time (P < 0.05), representing only 11 ± 1%, 35 ± 1% and 43 ± 1%, respectively, of original photon emitting properties of the bacterial population by d 10. Photonic emissions were positively correlated with bacterial concentration (P < 0.05) for pAK1-lux, pCGLS-1 and pXEN-1 (r = 0.96, 0.98 and 0.82, respectively). When stratified by high, medium and low density bacteria concentrations, photonic emissions for high density populations containing pAK1-lux, pCGLS-1 and pXEN-1 resulted in differences of photonic emissions across a range of bacterial concentrations (1 × 107 to 1 × 109 CFU, P < 0.05) with positive correlations (P < 0.05) of (r = 0.72, 0.46 and 0.72, respectively). The correlation of photonic emissions with bacterial concentrations for samples with medium and low density bacteria (pAK1-lux, pCGLS-1, and pXEN-1 plasmids) imaged in tubes were also positively correlated (medium; r = 0.69, 0.49, 0.46, low; r = 0.90, 0.71, 0.68, respectively; P > 0.05); although photonic emissions across a range of bacterial concentrations were not different (1 × 104 to 1 × 106 CFU, P > 0.05). For very low density bacterial concentrations imaged in 96 well plates photonic emissions were positively correlated with bacterial concentration (P < 0.05) for pAK1-lux, pCGLS-1, and pXEN-1 plasmids (r = 0.99, 0.99, and 0.96, respectively), and photonic emissions across a range of bacterial concentrations (1 × 103 to 1 × 105 CFU) low to high were different in the 96-well plate format (P < 0.05).ConclusionThese data characterize photon stability properties for S. typh-lux transformed with three different photon generating plasmids that may facilitate real-time Salmonella tracking using in vivo or in situ biophotonic paradigms.

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Development of bioluminescent Salmonella strains for use in food safety

Cited by 22 publications

References 38 publications

Development of stable reporter system cloning luxCDABE genes into chromosome of Salmonella enterica serotypes using Tn7 transposon

Development of stable reporter system cloning luxCDABE genes into chromosome of Salmonella enterica serotypes using Tn7 transposon

Investigation of Medium Chain Fatty Acid Feed Supplementation for ReducingSalmonellaTyphimurium Colonization in Turkey Poults

Photonic plasmid stability of transformed Salmonella Typhimurium: A comparison of three unique plasmids

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