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Respective roles of culturable and viable-but-nonculturable cells in the heterogeneity of Salmonella enterica serovar typhimurium invasiveness
- Source :
- Applied and environmental microbiology. 75(16)
- Publication Year :
- 2009
-
Abstract
- The existence of Salmonella enterica serovar Typhimurium viable-but-nonculturable (VBNC) cells is a public health concern since they could constitute unrecognized sources of infection if they retain their pathogenicity. To date, many studies have addressed the ability of S . Typhimurium VBNC cells to remain infectious, but their conclusions are conflicting. An assumption could explain these conflicting results. It has been proposed that infectivity could be retained only temporarily after entry into the VBNC state and that most VBNC cells generated under intense stress could exceed the stage where they are still infectious. Using a Radioselectan density gradient centrifugation technique makes it possible to increase the VBNC-cell/culturable-cell ratio without increasing the exposure to stress and, consequently, to work with a larger proportion of newly VBNC cells. Here, we observed that (i) in the stationary phase, the S . Typhimurium population comprised three distinct subpopulations at 10, 24, or 48 h of culture; (ii) the VBNC cells were detected at 24 and 48 h; (iii) measurement of invasion gene ( hilA , invF , and orgA ) expression demonstrated that cells are highly heterogeneous within a culturable population; and (iv) invasion assays of HeLa cells showed that culturable cells from the different subpopulations do not display the same invasiveness. The results also suggest that newly formed VBNC cells are either weakly able or not able to successfully initiate epithelial cell invasion. Finally, we propose that at entry into the stationary phase, invasiveness may be one way for populations of S . Typhimurium to escape stochastic alteration leading to cell death.
- Subjects :
- Salmonella typhimurium
Population
Colony Count, Microbial
Virulence
Public Health Microbiology
Applied Microbiology and Biotechnology
Viable but nonculturable
Microbiology
Bacterial Proteins
Centrifugation, Density Gradient
Humans
education
Infectivity
Differential centrifugation
education.field_of_study
Microbial Viability
Ecology
biology
Gene Expression Regulation, Bacterial
biology.organism_classification
Enterobacteriaceae
Culture Media
DNA-Binding Proteins
Cell culture
Salmonella enterica
Trans-Activators
Food Science
Biotechnology
HeLa Cells
Transcription Factors
Subjects
Details
- ISSN :
- 10985336
- Volume :
- 75
- Issue :
- 16
- Database :
- OpenAIRE
- Journal :
- Applied and environmental microbiology
- Accession number :
- edsair.doi.dedup.....a4e55bbe666cc064d8da6a3c4fc6e167