Survival and Filamentation of
            <i>Salmonella enterica</i>
            Serovar Enteritidis PT4 and
            <i>Salmonella enterica</i>
            Serovar Typhimurium DT104 at Low Water Activity

Mattick, Karen; Jørgensen, Frieda; Legan, J.D.; Cole, M.; Porter, Jonathan; Lappin-Scott, H. M.; Humphrey, T. J.

doi:10.1128/aem.66.4.1274-1279.2000

Cited by 133 publications

(121 citation statements)

References 38 publications

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“…They found that filament formation with increased filament length became apparent in 5% sodium chloride and 7% potassium chloride (Zarei et al, 2012). These findings were also observed in Salmonella at low water activity and low temperature (Mattick et al, 2000(Mattick et al, , 2003.…”

Section: Resistance To Bacteriocinssupporting

confidence: 65%

The Effects of Sodium Chloride on the Physiological Characteristics of Listeria monocytogenes

Choi¹,

Yoon²

2013

Korean Journal for Food Science of Animal Resources

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Sodium chloride is used to improve various properties of processed meat products, e.g., taste, preservation, water binding capacity, texture, meat batter viscosity, safety, and flavor; however, many studies have shown that sodium chloride increases the resistance of many foodborne pathogens to heat and acid. Listeria monocytogenes has been isolated from various readyto-eat (RTE) meat and dairy products formulated with sodium chloride; therefore, the objective of this paper was to review the effects of sodium chloride on the physiological characteristics of L. monocytogenes. The exposure of L. monocytogenes to sodium chloride may increase biofilm formation on foods or food contact surfaces, virulence gene transcription, invasion of Caco-2 cells, and bacteriocin production, depending on L. monocytogenes strain and serotype as well as sodium chloride concentration. When L. monocytogenes cells were exposed to sodium chloride, their resistance to UV-C irradiation and freezing temperatures increased, but sodium chloride had no effect on their resistance to gamma irradiation. The morphological properties of L. monocytogenes, especially cell elongation and filament formation, also change in response to sodium chloride. These findings indicate that sodium chloride affects various physiological responses of L. monocytogenes and thus, the effect of sodium chloride on L. monocytogenes in RTE meat and dairy products needs to be considered with respect to food safety. Moreover, further studies of microbial risk assessment should be conducted to suggest an appropriate sodium chloride concentration in animal origin foods.

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Section: Resistance To Bacteriocinssupporting

confidence: 65%

The Effects of Sodium Chloride on the Physiological Characteristics of Listeria monocytogenes

Choi¹,

Yoon²

2013

Korean Journal for Food Science of Animal Resources

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“…It is interesting to speculate that extracytoplasmic stress response functions regulated by s E would be required for survival of Salmonella in other microenvironments where conditions of osmotic shock may be experienced (Mattick et al, 2000). These might include bile salts and foods with low a w properties, for example.…”

Section: Resultsmentioning

confidence: 99%

Role of the alternative sigma factors σ E and σ S in survival of Salmonella enterica serovar Typhimurium during starvation, refrigeration and osmotic shock

et al. 2007

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The ability of Salmonella enterica serovar Typhimurium to survive environmental stress requires specific, coordinated, responses, which induce resistance to the stress condition. This study investigated the relative contribution of s E and s S , the sigma factors regulating extracytoplasmic and general stress response functions, respectively, to survival at low temperature and also in media of differing osmotic strength, conditions relevant to food preservation. To determine if low-temperature storage is a signal for s E -and s S -mediated survival, the ability of S. Typhimurium rpoE, rpoS and rpoE/rpoS mutants to survive in a saline starvation-survival model at a refrigeration temperature (4.5 6C) was examined. Under these conditions, the rpoE mutant was significantly (P<0.05) compromised compared to the parent and to an rpoS mutant. The double mutant in rpoE and rpoS displayed a cumulative defect in survival. In hyperosmotic environments (low a w ) containing 6 % NaCl and at refrigeration temperature, both sigma factors were important for maximum survival but s S played the dominant role. Analysis of the metabolic activity of starved populations at 4.5 and 37 6C revealed significantly (P<0.001) elevated electron-transport system activity in mutants in rpoE and rpoS, indicating a role for s E -and s S -regulated genes in maintaining energy homeostasis. Together these data demonstrate that s E and s S are important for survival of S. Typhimurium in conditions encountered during food processing and that the relative contribution of s E and s S is critically dependent on the precise nature of the stress.

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“…NaCl is one of the most important agents in food preservation, known since ancient times to be a potent microbial inhibitor. More recent studies show that NaCl and osmotic stress affect virulence factor expression in numerous bacterial species, such as Salmonella spp., Escherichia coli, and Helicobacter pylori (19,33,37).…”

mentioning

confidence: 99%

Hyperosmotic Stress Response of Campylobacter jejuni

et al. 2012

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The diarrheal pathogen Campylobacter jejuni and other gastrointestinal bacteria encounter changes in osmolarity in the environment, through exposure to food processing, and upon entering host organisms, where osmotic adaptation can be associated with virulence. In this study, growth profiles, transcriptomics, and phenotypic, mutant, and single-cell analyses were used to explore the effects of hyperosmotic stress exposure on C. jejuni. Increased growth inhibition correlated with increased osmotic concentration, with both ionic and nonionic stressors inhibiting growth at 0.620 total osmol liter ؊1 . C. jejuni adaptation to a range of osmotic stressors and concentrations was accompanied by severe filamentation in subpopulations, with microscopy indicating septum formation and phenotypic diversity between individual cells in a filament. Population heterogeneity was also exemplified by the bifurcation of colony morphology into small and large variants on salt stress plates. Flow cytometry of C. jejuni harboring green fluorescent protein (GFP) fused to the ATP synthase promoter likewise revealed bimodal subpopulations under hyperosmotic stress. We also identified frequent hyperosmotic stress-sensitive variants within the clonal wild-type population propagated on standard laboratory medium. Microarray analysis following hyperosmotic upshift revealed enhanced expression of heat shock genes and genes encoding enzymes for synthesis of potential osmoprotectants and cross-protective induction of oxidative stress genes. The capsule export gene kpsM was also upregulated, and an acapsular mutant was defective for growth under hyperosmotic stress. For C. jejuni, an organism lacking most conventional osmotic response factors, these data suggest an unusual hyperosmotic stress response, including likely "bet-hedging" survival strategies relying on the presence of stress-fit individuals in a heterogeneous population.

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Survival and Filamentation of Salmonella enterica Serovar Enteritidis PT4 and Salmonella enterica Serovar Typhimurium DT104 at Low Water Activity

Cited by 133 publications

References 38 publications

The Effects of Sodium Chloride on the Physiological Characteristics of Listeria monocytogenes

The Effects of Sodium Chloride on the Physiological Characteristics of Listeria monocytogenes

Role of the alternative sigma factors σ E and σ S in survival of Salmonella enterica serovar Typhimurium during starvation, refrigeration and osmotic shock

Hyperosmotic Stress Response of Campylobacter jejuni

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