Survival of
            <i>Listeria monocytogenes</i>
            in sea water and effect of exposure on thermal resistance

Bremer, Phil; Osborne, Carolyn M.; Kemp, Roslyn A.; Smith, James J.

doi:10.1046/j.1365-2672.1998.853533.x

Cited by 26 publications

(14 citation statements)

References 37 publications

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“…1b). During further starvation, the proportion of cells with a vp decreased from 1.5U10 7 to 5.0U10 6 , but this decline (33%) was not consistent with the decrease in cell viability as estimated by cfu, where a 99.99% reduction in viability was observed (Fig. 1b).…”

Section: Cell Viability and Survival Of S Pyogenes In The Stationarymentioning

confidence: 81%

Survival of Streptococcus pyogenes under stress and starvation

Trainor

1999

FEMS Microbiology Letters

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The ability of Streptococcus pyogenes to enter a quiescent state, similar to the stationary phase of lab cultures, is believed to be an important factor in its ability to persist within the host and to subsequently cause disease. Using a model broth system, we determined that after entering the stationary phase, there was a 99.99% reduction in cell viability over a 4-day period, following which the cells appeared to enter a resistant starvation state where cell numbers remained constant over the subsequent 3^4 weeks. This starvation response was induced by carbon or phosphorous limitation, but not by nitrogen limitation in the form of amino acids where cells became non-culturable after 4 days. Amino acid utilization in the absence of a carbon source may be an essential factor for the long-term survival of this bacterium in the stationary phase. Early stationary phase cells showed a greater resistance to oxidative and pH stress compared to 24-h-starved cultures. There was evidence for the formation of a viable but non-culturable state as indicated by a comparison of the numbers of cells with a functional membrane potential (rhodamine 123) against culturable cells on either Todd Hewitt broth agar or sheep blood agar. Long-term survival of S. pyogenes was dependent on both cell wall and protein synthesis, suggesting that starving cultures are a dynamic cell population. ß

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Section: Cell Viability and Survival Of S Pyogenes In The Stationarymentioning

confidence: 81%

Survival of Streptococcus pyogenes under stress and starvation

Trainor

1999

FEMS Microbiology Letters

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“…However, while some studies don’t dispute that L. monocytogenes can be isolated from water, they do disregard it as an important source of contamination within fish farms (Jemmi and Keusch, 1994; Rorvik et al, 2000). More recent studies have also shown the survival of the pathogen in seawater, although many of these report that the survival of L. monocytogenes is strain and temperature dependent with lower temperatures correlating with higher survival (Bremer et al, 1998; Hsu et al, 2005; Hansen et al, 2006). However, besides temperature, other factors must also be considered for the survival of L. monocytogenes in seawater.…”

Section: Entry Of L Monocytogenes Into the Food Chainmentioning

confidence: 99%

The Role of Stress and Stress Adaptations in Determining the Fate of the Bacterial Pathogen Listeria monocytogenes in the Food Chain

2016

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The foodborne pathogen Listeria monocytogenes is a highly adaptable organism that can persist in a wide range of environmental and food-related niches. The consumption of contaminated ready-to-eat foods can cause infections, termed listeriosis, in vulnerable humans, particularly those with weakened immune systems. Although these infections are comparatively rare they are associated with high mortality rates and therefore this pathogen has a significant impact on food safety. L. monocytogenes can adapt to and survive a wide range of stress conditions including low pH, low water activity, and low temperature, which makes it problematic for food producers who rely on these stresses for preservation. Stress tolerance in L. monocytogenes can be explained partially by the presence of the general stress response (GSR), a transcriptional response under the control of the alternative sigma factor sigma B (σB) that reconfigures gene transcription to provide homeostatic and protective functions to cope with the stress. Within the host σB also plays a key role in surviving the harsh conditions found in the gastrointestinal tract. As the infection progresses beyond the GI tract L. monocytogenes uses an intracellular infectious cycle to propagate, spread and remain protected from the host’s humoral immunity. Many of the virulence genes that facilitate this infectious cycle are under the control of a master transcriptional regulator called PrfA. In this review we consider the environmental reservoirs that enable L. monocytogenes to gain access to the food chain and discuss the stresses that the pathogen must overcome to survive and grow in these environments. The overlap that exists between stress tolerance and virulence is described. We review the principal measures that are used to control the pathogen and point to exciting new approaches that might provide improved means of control in the future.

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“…Appropriate serial decimal dilutions were made in sterile physiological water. Counts of L. innocua were determined in triplicate using the drop-plate method (Bremer, Osborne, Kemp, & Smith, 1998) by platting cell suspension on selective medium for enumeration of Listeria (PALCAM, Difco Laboratories, Detroit, USA). Colonies were counted after 48 h incubation at 37°C.…”

Section: Microbiological Analyses Of Cheese Samplesmentioning

confidence: 99%