scholarly journals Respective Roles of Culturable and Viable-but-Nonculturable Cells in the Heterogeneity of Salmonella enterica Serovar Typhimurium Invasiveness

2009 ◽  
Vol 75 (16) ◽  
pp. 5179-5185 ◽  
Author(s):  
Julien Passerat ◽  
Patrice Got ◽  
Sam Dukan ◽  
Patrick Monfort
Keyword(s):  
Stationary Phase ◽  
Salmonella Enterica ◽  
Gradient Centrifugation ◽  
Health Concern ◽  
Viable But Nonculturable ◽  
Serovar Typhimurium ◽  
Nonculturable Cells ◽  
Sources Of Infection ◽  
Culturable Cell ◽  
Vbnc Cell

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.

scholarly journals Induction and Resuscitation of Viable but Nonculturable Salmonella enterica Serovar Typhimurium DT104†

2003 ◽  
Vol 69 (11) ◽  
pp. 6669-6675 ◽  
Author(s):  
A. R. Gupte ◽  
C. L. E. de Rezende ◽  
S. W. Joseph
Keyword(s):  
Salmonella Enterica ◽  
Structural Integrity ◽  
Multidrug Resistant ◽  
Resistant Organism ◽  
Viable But Nonculturable ◽  
Growth And Survival ◽  
Serovar Typhimurium ◽  
Periodic Monitoring ◽  
Nonculturable Cells ◽  
Adverse Environmental Conditions

ABSTRACT Salmonella enterica serovar Typhimurium DT104 11601was tested for its ability to maintain viability in minimal, chemically defined solutions. Periodic monitoring of growth and survival in microcosms of different ion concentrations, maintained at various temperatures, showed a gradual decline in culturable organisms (∼235 days) at 5°C. Organisms maintained at a higher temperature (21°C) showed continuous, equivalent CFU per milliliter (∼106) up to 400 days after inoculation. Fluorescence microscopy with Baclight revealed that nonculturable cells were actually viable, while observations with scanning electron microscopy showed that the cells had retained their structural integrity. Temperature upshift (56°C ± 0.5, 15 s) of the nonculturable organisms (5°C) in Trypticase soy broth followed by immediate inoculation onto Trypticase soy agar (TSA) gave evidence of resuscitation. Interestingly, S. enterica serovar Typhimurium DT104 from the microcosms at either 5°C (1 to 200 days) or 21°C (1 to 250 days) did not show enhanced growth after intermittent inoculation onto catalase-supplemented TSA. Furthermore, cells from 21°C microcosms exposed to oxidative and osmotic stress showed greater resistance to stresses over increasing times of exposure than did recently grown cells. It is possible that the exceptional survivability and resilience of this particular strain may in part reflect the growing importance of this multidrug-resistant organism, in general, as a cause of intestinal disease in humans. The fact that S. enterica serovar Typhimurium DT104 11601 is capable of modifying its physiological characteristics, including entry into and recovery from the viable but nonculturable state, suggests the overall possibility that S. enterica serovar Typhimurium DT104 may be able to respond uniquely to various adverse environmental conditions.

Integration host factor alleviates H-NS silencing of the Salmonella enterica serovar Typhimurium master regulator of SPI1, hilA

Microbiology ◽  
2011 ◽  
Vol 157 (9) ◽  
pp. 2504-2514 ◽  
Author(s):  
Mário H. Queiroz ◽  
Cristina Madrid ◽  
Sònia Paytubi ◽  
Carlos Balsalobre ◽  
Antonio Juárez
Keyword(s):  
Stationary Phase ◽  
Salmonella Enterica ◽  
Growth Conditions ◽  
Integration Host Factor ◽  
Band Shift ◽  
Global Regulators ◽  
Serovar Typhimurium ◽  
Associated Proteins ◽  
Transcription Data

Coordination of the expression of Salmonella enterica invasion genes on Salmonella pathogenicity island 1 (SPI1) depends on a complex circuit involving several regulators that converge on expression of the hilA gene, which encodes a transcriptional activator (HilA) that modulates expression of the SPI1 virulence genes. Two of the global regulators that influence hilA expression are the nucleoid-associated proteins Hha and H-NS. They interact and form a complex that modulates gene expression. A chromosomal transcriptional fusion was constructed to assess the effects of these modulators on hilA transcription under several environmental conditions as well as at different stages of growth. The results obtained showed that these proteins play a role in silencing hilA expression at both low temperature and low osmolarity, irrespective of the growth phase. H-NS accounts for the main repressor activity. At high temperature and osmolarity, H-NS-mediated silencing completely ceases when cells enter the stationary phase, and hilA expression is induced. Mutants lacking IHF did not induce hilA in cells entering the stationary phase, and this lack of induction was dependent on the presence of H-NS. Band-shift assays and in vitro transcription data showed that for hilA induction under certain growth conditions, IHF is required to alleviate H-NS-mediated silencing.

Identification of Salmonella enterica serovar Typhimurium genes associated with growth suppression in stationary-phase nutrient broth cultures and in the chicken intestine

2002 ◽  
Vol 178 (6) ◽  
pp. 411-420 ◽  
Author(s):  
Ivan Rychlik ◽  
Gerald Martin ◽  
Ulrich Methner ◽  
Margaret Lovell ◽  
Lenka Cardova ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Growth Suppression ◽  
Nutrient Broth ◽  
Chicken Intestine ◽  
Serovar Typhimurium

scholarly journals In vitro synergistic potentials of novel antibacterial combination therapies against Salmonella enterica serovar Typhimurium

2020 ◽  
Author(s):  
Md. Akil Hossain ◽  
Hae-Chul Park ◽  
Kwang-jick Lee ◽  
Sung-Won Park ◽  
Seung-Chun Park ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Clinical Importance ◽  
Farm Animals ◽  
Health Concern ◽  
Epicatechin Gallate ◽  
Serovar Typhimurium

Abstract Background: The antibiotics generally used in farm animals are rapidly losing their effectiveness all over the world as bacteria develop antibiotic resistance. Like some other pathogenic bacteria multidrug-resistant strains of Salmonella enterica serovar Typhimurium (S. Typhimurium) are also frequently found in animals and humans which poses a major public health concern. New strategies are needed to block the development of resistance and to prolong the life of traditional antibiotics. Thus, this study aimed to increase the efficacy of existing antibiotics against S. Typhimurium by combining them with opportunistic phenolic compounds gallic acid (GA), epicatechin, epicatechin gallate, epigallocatechin and hamamelitannin. Fractional inhibitory concentration indexes (FICI) of phenolic compound-antibiotic combinations against S. Typhimurium were determined. Based on the FICI and clinical importance, 1 combination (GA and ceftiofur) was selected for evaluating its effects on the virulence factors of this bacterium. Viability of Rattus norvegicus (IEC-6) cell in presence of this antibacterial combination was evaluated.Results: Minimum inhibitory concentrations (MICs) of GA, epigallocatechin and hamamelitannin found against different strains of S. Typhimurium were 256, (512–1024), and (512–1024) μg/mL, respectively. Synergistic antibacterial effect was obtained from the combination of erythromycin-epicatechin gallate (FICI: 0.50) against S. Typhimurium. Moreover, additive effects (FICI: 0.502–0.750) were obtained from 16 combinations against this bacterium. The time-kill assay and ultrastructural morphology showed that GA-ceftiofur combination more efficiently inhibited the growth of S. Typhimurium compared to individual antimicrobials. Biofilm viability, and swimming and swarming motilities of S. Typhimurium in presence of GA-ceftiofur combination were more competently inhibited than individual antimicrobials. Viabilities of IEC-6 cells were more significantly enhanced by GA-ceftiofur combinations than these antibacterials alone.Conclusions: This study suggests that GA-ceftiofur combination can be potential medication to treat S. Typhimurium-associated diarrhea and prevent S. Typhimurium-associated blood-stream infections (e.g.: fever) in farm animals, and ultimately its transmission from animal to human. Further in vivo study to confirm these effects and safety profiles in farm animal should be undertaken for establishing these combinations as medications.

scholarly journals Effect of Growth Temperature on Crl-Dependent Regulation of σS Activity in Salmonella enterica Serovar Typhimurium

2008 ◽  
Vol 190 (13) ◽  
pp. 4453-4459 ◽  
Author(s):  
Véronique Robbe-Saule ◽  
Ingrid Carreira ◽  
Annie Kolb ◽  
Françoise Norel
Keyword(s):  
Stationary Phase ◽  
Salmonella Enterica ◽  
Regulatory Protein ◽  
Effect Of Temperature ◽  
Resistance Level ◽  
Serovar Typhimurium ◽  
Negative Effect ◽  
Transcription In Vitro ◽  
Physiological Impact

ABSTRACT The small regulatory protein Crl favors association of the stationary-phase sigma factor σS (RpoS) with the core enzyme polymerase and thereby increases σS activity. Crl has a major physiological impact at low levels of σS. Here, we report that the Crl effects on σS-dependent gene expression, the H2O2 resistance of Salmonella enterica serovar Typhimurium, and the resistance of this organism to acidic pH are greater at 28°C than at 37°C. Immunoblot experiments revealed a negative correlation between σS and Crl levels; the production of Crl was slightly greater at 28°C than at 37°C, whereas the σS levels were about twofold lower at 28°C than at 37°C. At both temperatures, Crl was present in excess of σS, and increasing the Crl level further did not increase the H2O2 resistance level of Salmonella and the expression of the σS-dependent gene katE encoding the stationary-phase catalase. In contrast, increasing the σS level rendered Salmonella more resistant to H2O2 at 28°C, increased the expression of katE, and reduced the magnitude of Crl activation. In addition, the effect of Crl on katE transcription in vitro was not dependent on temperature. These results suggest that the effect of temperature on Crl-dependent regulation of the katE gene and H2O2 resistance are mediated mainly via an effect on σS levels. In addition, our results revealed that σS exerts a negative effect on the production of Crl in stationary phase when the cells contain high levels of σS.

ppGpp-mediated stationary phase induction of the genes encoded by horizontally acquired pathogenicity islands and cob/pdu locus in Salmonella enterica serovar Typhimurium

2010 ◽  
Vol 48 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Miryoung Song ◽  
Hyun-Ju Kim ◽  
Sangryeol Ryu ◽  
Hyunjin Yoon ◽  
Jiae Yun ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Pathogenicity Islands ◽  
Serovar Typhimurium

ANALYSIS OF THE EFFECT OF PHAGES ON BACTERIA AND THEIR VIABLE BUT NONCULTURABLE CELLS

2021 ◽  
Vol 1 (3) ◽  
pp. 317-322
Author(s):  
T.A. Karachina ◽  
◽  
A.M. Abdullaeva ◽  
L.P. Blinkova ◽  
Yu.D. Pakhomov ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Raw Materials ◽  
Animal Origin ◽  
Meat Processing ◽  
Viable But Nonculturable ◽  
Chemical Substances ◽  
E Coli ◽  
Processing Plants ◽  
Nonculturable Cells ◽  
Alternative Means

The growth in the use of antibiotic and chemical substances in meat processing plants shows the need to search for alternative means of decontamination, the most promising of which are bacteriophages. However, there are a lot of little-studied questions on their use, one of which is the effect of bacteriophages on viable but nonculturable (VBNC) cells of bacteria. In this regard, the article provides data on the analysis of the activity of commercial bacteriophages in relation to bacteriacontaminants of raw materials of animal origin, in particular E. coli and Salmonella enterica typhimurium, as well as their VBNC-cells.

scholarly journals Protein Content of Polyhedral Organelles Involved in Coenzyme B12-Dependent Degradation of 1,2-Propanediol in Salmonella enterica Serovar Typhimurium LT2

2003 ◽  
Vol 185 (17) ◽  
pp. 5086-5095 ◽  
Author(s):  
Gregory D. Havemann ◽  
Thomas A. Bobik
Keyword(s):  
Gel Electrophoresis ◽  
Salmonella Enterica ◽  
Sequence Similarity ◽  
Gradient Centrifugation ◽  
Two Dimensional Gel Electrophoresis ◽  
Protein Mass ◽  
Catalytic Function ◽  
Diol Dehydratase ◽  
Serovar Typhimurium ◽  
Shell Proteins

ABSTRACT Salmonella enterica forms polyhedral organelles during coenzyme B12-dependent growth on 1,2-propanediol (1,2-PD). Previously, these organelles were shown to consist of a protein shell partly composed of the PduA protein, the majority of the cell's B12-dependent diol dehydratase, and additional unidentified proteins. In this report, the polyhedral organelles involved in B12-dependent 1,2-PD degradation by S. enterica were purified by a combination of detergent extraction and differential and density gradient centrifugation. The course of the purification was monitored by electron microscopy and gel electrophoresis, as well as enzymatic assay of B12-dependent diol dehydratase. Following one- and two-dimensional gel electrophoresis of purified organelles, the identities and relative abundance of their constituent proteins were determined by N-terminal sequencing, protein mass fingerprinting, Western blotting, and densitometry. These analyses indicated that the organelles consisted of at least 15 proteins, including PduABB′CDEGHJKOPTU and one unidentified protein. Seven of the proteins identified (PduABB′JKTU) have some sequence similarity to the shell proteins of carboxysomes (a polyhedral organelle involved in autotrophic CO2 fixation), suggesting that the S. enterica organelles and carboxysomes have a related multiprotein shell. In addition, S. enterica organelles contained four enzymes: B12-dependent diol dehydratase, its putative reactivating factor, aldehyde dehydrogenase, and ATP cob(I)alamin adenosyltransferase. This complement of enzymes indicates that the primary catalytic function of the S. enterica organelles is the conversion of 1,2-PD to propionyl coenzyme A (which is consistent with our prior proposal that the S. enterica organelles function to minimize aldehyde toxicity during growth on 1,2-PD). The possibility that similar protein-bound organelles may be more widespread in nature than currently recognized is discussed.

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