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Esteban-Cuesta I, Labrador M, Hunt K, Reese S, Fischer J, Schwaiger K, Gareis M. Phenotypic and Genetic Comparison of a Plant-Internalized and an Animal-Isolated Salmonella Choleraesuis Strain. Microorganisms 2021; 9:microorganisms9081554. [PMID: 34442630 PMCID: PMC8398053 DOI: 10.3390/microorganisms9081554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/05/2021] [Accepted: 07/16/2021] [Indexed: 11/16/2022] Open
Abstract
Contamination of fresh produce with human pathogens poses an important risk for consumers, especially after raw consumption. Moreover, if microorganisms are internalized, no removal by means of further hygienic measures would be possible. Human pathogenic bacteria identified in these food items are mostly of human or animal origin and an adaptation to this new niche and particularly for internalization would be presumed. This study compares a plant-internalized and an animal-borne Salmonella enterica subsp. enterica serovar Choleraesuis aiming at the identification of adaptation of the plant-internalized strain to its original environment. For this purpose, a phenotypical characterization by means of growth curves under conditions resembling the indigenous environment from the plant-internalized strain and further analyses using Pulsed-field gel electrophoresis and Matrix-assisted laser desorption ionization time of flight spectrometry were assessed. Furthermore, comparative genomic analyses by means of single nucleotide polymorphisms and identification of present/absent genes were performed. Although some phenotypical and genetic differences could be found, no signs of a specific adaptation for colonization and internalization in plants could be clearly identified. This could suggest that any Salmonella strain could directly settle in this niche without any evolutionary process being necessary. Further comparative analysis including internalized strains would be necessary to assess this question. However, these kinds of strains are not easily available.
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Affiliation(s)
- Irene Esteban-Cuesta
- Chair of Food Safety, Veterinary Faculty, LMU Munich, 85764 Oberschleissheim, Germany; (K.H.); (K.S.); (M.G.)
- Correspondence:
| | - Mirian Labrador
- Departamento de Producción Animal y Ciencia de los Alimentos, Veterinary Faculty, Instituto Agroalimentario de Aragon-IA2, University of Zaragoza-CITA, 50013 Zaragoza, Spain;
| | - Katharina Hunt
- Chair of Food Safety, Veterinary Faculty, LMU Munich, 85764 Oberschleissheim, Germany; (K.H.); (K.S.); (M.G.)
| | - Sven Reese
- Chair of Anatomy, Histology and Embryology, Department of Veterinary Sciences, Faculty of Veterinary Medicine, LMU Munich, 80539 Munich, Germany;
| | - Jennie Fischer
- National Salmonella Reference Laboratory, Unit Food Microbiology, Host-Pathogen-Interactions, Department of Biological Safety, German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung—BfR), 12277 Berlin, Germany;
| | - Karin Schwaiger
- Chair of Food Safety, Veterinary Faculty, LMU Munich, 85764 Oberschleissheim, Germany; (K.H.); (K.S.); (M.G.)
- Unit of Food Hygiene and Technology, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, 1220 Vienna, Austria
| | - Manfred Gareis
- Chair of Food Safety, Veterinary Faculty, LMU Munich, 85764 Oberschleissheim, Germany; (K.H.); (K.S.); (M.G.)
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