Contamination of the contents of intact eggs by <i>Salmonella typhimurium</i> DT104

Williams, Ann; Davies, Alison; Wilson, J. L.; Marsh, Philip; Leach, Steve; Humphrey, Tom J.

doi:10.1136/vr.143.20.562

Cited by 44 publications

(43 citation statements)

References 9 publications

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“…However, the strains tested did not appear more invasive than non-resistant cohorts and some DT104 isolates appeared even less invasive than non-resistant relatives [13]. With regard to invasion capacity, however, it is interesting to note that S. enterica Typhimurium DT104 infection resulted in a higher egg contamination rate than S. enterica Enteritidis PT4 [54]. In the mouse model of infection, multidrug-resistant DT104 strains did not reveal evidence of enhanced nor reduced virulence when compared with ATCC S. enterica Typhimurium strain 14028s [2].…”

Section: Change In Virulence?mentioning

confidence: 93%

Molecular characterization, spread and evolution of multidrug resistance in Salmonella enterica Typhimurium DT104

2001

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-Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104 has emerged during the last decade as a global health problem because of its involvement in diseases in animals and humans. Multidrug-resistant DT104 strains are mostly resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracyclines (ACSSuT resistance type). The genes coding for such resistances are clustered on the chromosome. This paper reviews new developments in the characterization of S. enterica Typhimurium DT104, its chromosomal antibiotic resistance genes and their spread among other S. enterica Typhimurium phage types and other S. enterica serovars, the development of specific detection methods, virulence characteristics, and the evolution of multidrugresistance with regard to the emergence of quinolone resistance.Salmonella Typhimurium DT104 / multidrug resistance / Salmonella genomic island I Résumé -Caractérisation moléculaire, diffusion et évolution de la résistance multiple aux antibiotiques chez Salmonella enterica Typhimurium DT104. Le lysotype DT104 de Salmonella enterica Typhimurium présentant une résistance multiple aux antibiotiques a émergé durant la dernière décennie comme un problème mondial de santé publique qui touche à la fois humains et animaux. Les souches du lysotype DT104 sont en général résistantes à l'ampicilline, au chloramphénicol, à la streptomycine, aux sulphamides et aux tétracyclines (profil de résistance ACSSuT). Les gènes codant pour ces résistances sont groupés sur le chromosome. Cet article présente une revue des derniers dévelop-pements dans la caractérisation de S. enterica Typhimurium DT104, ses gènes chromosomiques de résis-tance et leur diffusion chez d'autres lysotypes de S. enterica Typhimurium et d'autres serotypes de S. enterica, le développement de méthodes spécifiques de détection, les caractéristiques de virulence, et l'évolution de la résistance multiple au regard de l'émergence de la résistance aux quinolones.Salmonella Typhimurium DT104 / résistance multiple / îlot génomique I Vet. Res. 32 (2001) [301][302][303][304][305][306][307][308][309][310] 301

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Section: Change In Virulence?mentioning

confidence: 93%

Molecular characterization, spread and evolution of multidrug resistance in Salmonella enterica Typhimurium DT104

2001

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“…DT104 strain 30 (44), PT4 strain LA5, and PT4 strain EAV54 were used in this study. Strain 30 was isolated from cattle feces.…”

Section: Methodsmentioning

confidence: 99%

Habituation of Salmonella spp. at Reduced Water Activity and Its Effect on Heat Tolerance

Mattick

Jørgensen

Legan³

et al. 2000

Appl Environ Microbiol

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The effect of habituation at reduced water activity (a w ) on heat tolerance of Salmonella spp. was investigated. Stationary-phase cells were exposed to a w 0.95 in broths containing glucose-fructose, sodium chloride, or glycerol at 21°C for up to a week prior to heat challenge at 54°C. In addition, the effects of different a w s and heat challenge temperatures were investigated. Habituation at a w 0.95 resulted in increased heat tolerance at 54°C with all solutes tested. The extent of the increase and the optimal habituation time depended on the solute used. Exposure to broths containing glucose-fructose (a w 0.95) for 12 h resulted in maximal heat tolerance, with more than a fourfold increase in D 54 values. Cells held for more than 72 h in these conditions, however, became as heat sensitive as nonhabituated populations. Habituation in the presence of sodium chloride or glycerol gave rise to less pronounced but still significant increases in heat tolerance at 54°C, and a shorter incubation time was required to maximize tolerance. The increase in heat tolerance following habituation in broths containing glucose-fructose (a w 0.95) was RpoS independent. The presence of chloramphenicol or rifampin during habituation and inactivation did not affect the extent of heat tolerance achieved, suggesting that de novo protein synthesis was probably not necessary. These data highlight the importance of cell prehistory prior to heat inactivation and may have implications for food manufacturers using low-a w ingredients.

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“…Secondary models were developed for serovar Typhimurium DT104 strain 30 (62) such that inactivation curves could be predicted by interpolation for conditions not tested, and this was evaluated by using intermediate-moisture foods and different solutes to reduce a w . This paper demonstrates that, while low a w is protective for Salmonella at temperatures of Ͼ70°C, it promotes more rapid death at lower temperatures.…”

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confidence: 99%

Effect of Challenge Temperature and Solute Type on Heat Tolerance of Salmonella Serovars at Low Water Activity

Mattick

Jørgensen

Wang³

et al. 2001

Appl Environ Microbiol

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135

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Salmonella spp. are reported to have an increased heat tolerance at low water activity (a w ; measured by relative vapor pressure [rvp]), achieved either by drying or by incorporating solutes. Much of the published data, however, cover only a narrow treatment range and have been analyzed by assuming first-order death kinetics. In this study, the death of Salmonella enterica serovar Typhimurium DT104 when exposed to 54 combinations of temperature (55 to 80°C) and a w (rvp 0.65 to 0.90, reduced using glucose-fructose) was investigated. The Weibull model (LogS ‫؍‬ ؊bt n ) was used to describe microbial inactivation, and surface response models were developed to predict death rates for serovar Typhimurium at all points within the design surface. The models were evaluated with data generated by using six different Salmonella strains in place of serovar Typhimurium DT104 strain 30, two different solutes in place of glucose-fructose to reduce a w , or six low-a w foods artificially contaminated with Salmonella in place of the sugar broths. The data demonstrate that, at temperatures of >70°C, Salmonella cells at low a w were more heat tolerant than those at a higher a w but below 65°C the reverse was true. The same patterns were generated when sucrose (rvp 0.80 compared with 0.90) or NaCl (0.75 compared with 0.90) was used to reduce a w , but the extent of the protection afforded varied with solute type. The predictions of thermal death rates in the low-a w foods were usually fail-safe, but the few exceptions highlight the importance of validating models with specific foods that may have additional factors affecting survival.

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Contamination of the contents of intact eggs by Salmonella typhimurium DT104

Cited by 44 publications

References 9 publications

Molecular characterization, spread and evolution of multidrug resistance in Salmonella enterica Typhimurium DT104

Molecular characterization, spread and evolution of multidrug resistance in Salmonella enterica Typhimurium DT104

Habituation of Salmonella spp. at Reduced Water Activity and Its Effect on Heat Tolerance

Effect of Challenge Temperature and Solute Type on Heat Tolerance of Salmonella Serovars at Low Water Activity

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