Influence of Bacterial Competitors on Salmonella enterica and Enterohemorrhagic Escherichia coli Growth in Microbiological Media and Attachment to Vegetable Seeds
Abstract
:1. Introduction
2. Materials and Methods
2.1. Bacterial Strains and Vegetable Seeds
2.2. Competitive Growth between Salmonella or EHEC and Selected Plant Pathogen, Probiotic Strain, or Biocontrol Agents in Microbiological Media
2.3. Competitive Attachment between Salmonella or EHEC and Selected Plant Pathogen, Probiotic Strain, or Biocontrol Agents to Vegetable Seeds
2.4. Effect of Metabolites in Cell-Free Supernatants (CFS) of the Spend Cultures of Biocontrol Agents and Probiotic Strain on Salmonella and EHEC
2.5. Statistical Analysis
3. Results
3.1. Competitive Growth between Salmonella/EHEC and Bacterial Competitors
3.2. Competitive Attachment to Vegetable Seeds by Salmonella/EHEC as Affected by Bacterial Competitors
3.3. Inhibition of Salmonella and EHEC by the CFS of L. rhamnousus GG Spent Cultures
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Data Availability Statement
Conflicts of Interest
References
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Nalidixic Acid Resistant Derivate | Serovar/Strain | Source |
---|---|---|
Salmonella enterica | Stanley | Sprout-related outbreak, Finland, Canada, and the US, 1997 |
Baildon | Tomato- and lettuce-related outbreaks, the US, 1999 | |
Montevideo | Tomato-related outbreak, the US, 1993 | |
Cubana | Sprout-related outbreak, the US, 2012 | |
Enterohemorrhagic Escherichia coli | F4546 | Sprout-related outbreak, the US, 1997 |
BAA-2326 | Fenugreek sprout-related outbreak, Germany, 2011 | |
K4492 | Spinach-related outbreak, the US, 2006 | |
H1730 | Lettuce-related outbreak, the US, 2003 | |
Pseudomonas fluorescenes | A506 | Commercial biocontrol agent for Erwinia amylovora (fire blight) on fruits |
Bacillus mojavensis | RRC 101 | Commercial biocontrol agent for Fusarium verticillioides in maize and other crops; surfactin-producing |
Bacillus subtilis | ATCC 6051 | surfactin-producing strain |
Lactobacillus rhamnosus | GG | Commercial probiotic |
Pseudomonas syringae pv. tomato | DC 3000 | Frequent seed-borne pathogen on tomato plant |
Main Effect | Mean Population of Salmonella or EHEC (log CFU/mL) as Influenced by | Main Effect | Mean Population (log CFU/mL) of Salmonella and EHEC as Influenced by | |
---|---|---|---|---|
S. enterica1 (n = 540) | E. coli2 (n = 540) | |||
Competitive bacteria presence | S. enterica strains used | |||
Control (n = 60) | 7.8 ± 0.26 A | 8.1 ± 0.26 A | S. Montevideo (n = 135) | 6.8 ± 0.19 A |
P. syringae pv. tomato DC 3000 (n = 60) | 7.4 ± 0.24 B | 7.8 ± 0.26 B | S. Baildon (n = 135) | 6.6 ± 0.19 A |
B. subtilis ATCC 6051 (n = 60) | 7.3 ± 0.22 BC | 7.6 ± 0.25 C | S. Stanley (n = 135) | 6.1 ± 0.20 B |
B. mojavensis RRC 101 (n = 60) | 7.2 ± 0.21 C | 7.5 ± 0.24 C | S. Cubana (n = 135) | 6.1 ± 0.19 B |
P. fluorescenes A506 (n = 60) | 7.0 ± 0.22 D | 7.4 ± 0.24 D | E. coli strains used | |
Cocktail 1 3 (n = 60) | 6.9 ± 0.24 D | 7.3 ± 0.24 D | E. coli H1730 (n = 135) | 7.9 ± 0.12 A |
Cocktail 2 4 (n = 60) | 6.9 ± 0.24 D | 7.2 ± 0.24 E | E. coli K4492 (n =135) | 7.7 ± 0.13 A |
L. rhamnosus GG (25 °C; n = 60) | 6.0 ± 0.23 E | 6.8 ± 0.22 F | E. coli F4546 (n = 135) | 7.1 ± 0.17 B |
L. rhamnosus GG (37 °C; n = 60) | 2.5 ± 0.31 F | 6.6 ± 0.15 G | E. coli BAA 2326 (n = 135) | 6.4 ± 0.17 C |
Sampling points (h) used | ||||
24 (n = 108) | 7.5 ± 0.15 A | 8.7 ± 0.07 B | ||
48 (n = 108) | 7.5 ± 0.23 A | 9.0 ± 0.06 A | ||
72 (n = 108) | 6.9 ± 0.26 B | 8.4 ± 0.10 C | ||
12 (n = 108) | 6.2 ± 0.12 C | 6.3 ± 0.14 D | ||
6 (n = 108) | 3.8 ± 0.24 D | 4.1 ± 0.11 E |
Salmonella Strains | Mean Population of Salmonella 1 (log CFU/mL) (n = 480) | |||||||
---|---|---|---|---|---|---|---|---|
P. fluorescens A506 | Cocktail 2 | Cocktail 1 | L. rhamnosus GG | Pst DC3000 | B. mojavensis RRC101 | Control | B. subtilis ATCC6051 | |
Montevideo (n = 15) | 7.6 ± 0.39 aAB | 7.4 ± 0.44 aAB | 7.3 ± 0.44aAB | 6.5 ± 0.39 aB | 7.8 ± 0.45 aA | 7.6 ± 0.40 aAB | 8.0 ± 0.55 aA | 7.6 ± 0.41 aAB |
Baildon (n = 15) | 7.2 ± 0.45 aA | 7.2 ± 0.46 aA | 7.4 ± 0.46 aA | 5.9 ± 0.53 aB | 7.8 ± 0.41 aA | 7.4 ± 0.39 aA | 8.0 ± 0.49 aA | 7.6 ± 0.38 aA |
Stanley (n = 15) | 6.8 ± 0.47 aAB | 6.3 ± 0.46 aAB | 6.5 ± 0.48aAB | 5.7 ± 0.47 aB | 7.2 ± 0.46 aA | 7.0 ± 0.45 aAB | 7.5 ± 0.56 aA | 7.0 ± 0.49 aAB |
Cubana (n = 15) | 6.5 ± 0.46 aAB | 6.5 ± 0.54 aAB | 6.5 ± 0.45 aAB | 5.9 ± 0.49 aB | 6.8 ± 0.54 aAB | 6.8 ± 0.45 aAB | 7.9 ± 0.50 aA | 6.8 ± 0.47 aAB |
EHEC Strains | Mean Population of EHEC 1 (log CFU/mL) (n = 480) | |||||||
---|---|---|---|---|---|---|---|---|
P. fluorescens A506 | Cocktail 2 | Cocktail 1 | L. rhamnosus GG | Pst DC3000 | B. mojavensis RRC101 | Control | B. subtilis ATCC6051 | |
H1730 (n = 15) | 8.2 ± 0.30 aAB | 7.5 ± 0.35 abAB | 7.7 ± 0.35 abAB | 7.4 ± 0.38 aB | 8.6 ± 0.33 aAB | 8.2 ± 0.33 aAB | 8.6 ± 0.42 abA | 8.3 ± 0.32 aAB |
K4492 (n = 15) | 8.1 ± 0.40 aAB | 7.6 ± 0.43 aAB | 7.7 ± 0.42 aAB | 7.1 ± 0.46 aB | 8.4 ± 0.38 aA | 8.3 ± 0.38 aA | 8.7 ± 0.41 aA | 8.3 ± 0.39 aA |
F4546 (n = 15) | 6.9 ± 0.56 abA | 7.3 ± 0.58 abA | 7.3 ± 0.56 abA | 6.7 ± 0.47 aA | 7.7 ± 0.52 abA | 7.3 ± 0.53 abA | 7.9 ± 0.52 abA | 7.2 ± 0.54 abA |
BAA2326 (n = 15) | 6.3 ± 0.48 bA | 6.2 ± 0.53 bA | 6.6 ± 0.49 bA | 6.0 ± 0.43 aA | 6.6 ± 0.60 bA | 6.7 ± 0.57 bA | 7.3 ± 0.65 bA | 6.6 ± 0.59 bA |
Percentage (%) of Attached Cells | ||
---|---|---|
Salmonella1 (n = 84) | EHEC (n = 84) | |
As influenced by competitive strains | ||
Control (n = 12) | 10.5 ± 0.38 A | 3.9 ± 0.14 A |
L. rhamnosus GG (n = 12) | 9.4 ± 0.33 B | 3.4 ± 0.11 B |
Cocktail 2 2 (n = 12) | 9.0 ± 0.29 C | 3.1 ± 0.18 C |
B. mojavensis RRC 101 (n = 12) | 7.9 ± 0.21 D | 2.9 ± 0.16 C |
B. subtilis ATCC 6051 (n = 12) | 8.1 ± 0.24 D | 2.8 ± 0.23 C |
P. syringae pv. tomato DC 3000 (n = 12) | 8.2 ± 0.27 D | 3.5 ± 0.20 B |
P. fluorescenes A506 (n = 12) | 7.0 ± 0.20 E | 2.4 ± 0.12 D |
On different seed types | ||
Fenugreek (n = 21) | 12.5 ± 0.19 A | 6.7 ± 0.11 A |
Alfalfa (n = 21) | 11.8 ± 0.08 B | 2.0 ± 0.08 B |
Lettuce (n = 21) | 8.9 ± 0.08 C | 1.7 ± 0.04 C |
Tomato (n = 21) | ND 3 | ND |
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Liu, D.; Walcott, R.; Mis Solval, K.; Chen, J. Influence of Bacterial Competitors on Salmonella enterica and Enterohemorrhagic Escherichia coli Growth in Microbiological Media and Attachment to Vegetable Seeds. Foods 2021, 10, 285. https://doi.org/10.3390/foods10020285
Liu D, Walcott R, Mis Solval K, Chen J. Influence of Bacterial Competitors on Salmonella enterica and Enterohemorrhagic Escherichia coli Growth in Microbiological Media and Attachment to Vegetable Seeds. Foods. 2021; 10(2):285. https://doi.org/10.3390/foods10020285
Chicago/Turabian StyleLiu, Da, Ronald Walcott, Kevin Mis Solval, and Jinru Chen. 2021. "Influence of Bacterial Competitors on Salmonella enterica and Enterohemorrhagic Escherichia coli Growth in Microbiological Media and Attachment to Vegetable Seeds" Foods 10, no. 2: 285. https://doi.org/10.3390/foods10020285
APA StyleLiu, D., Walcott, R., Mis Solval, K., & Chen, J. (2021). Influence of Bacterial Competitors on Salmonella enterica and Enterohemorrhagic Escherichia coli Growth in Microbiological Media and Attachment to Vegetable Seeds. Foods, 10(2), 285. https://doi.org/10.3390/foods10020285